Add SoftLayer DNS provider (#59)

Add SoftLayer DNS as a DomainServiceProvider.

The SoftLayer API is a bit of a mess and treats MX and SRV records
differently. This leads to some replication and custom handling issues
to work around.

In this patch I have to change the SRV test case to be _tcp instead of
_protocol because softlayer requires a "known" protocol which AFAICT is
tcp, udp or tls. I think this will be acceptable in most cases.

Signed-off-by: Jamie Lennox <jamielennox@gmail.com>

vendor/github.com/softlayer/softlayer-go/config/config.go

@@ -0,0 +1,145 @@
+/**
+ * // This file is borrowed from https://github.com/vaughan0/go-ini/blob/master/ini.go
+ * // which is distributed under the MIT license (https://github.com/vaughan0/go-ini/blob/master/LICENSE).
+ *
+ * Copyright (c) 2013 Vaughan Newton
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
+ * associated documentation files (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the
+ * following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
+ * LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+// Package config provides functions for parsing INI configuration files.
+package config
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"regexp"
+	"strings"
+)
+
+var (
+	sectionRegex = regexp.MustCompile(`^\[(.*)\]$`)
+	assignRegex  = regexp.MustCompile(`^([^=]+)=(.*)$`)
+)
+
+// ErrSyntax is returned when there is a syntax error in an INI file.
+type ErrSyntax struct {
+	Line   int
+	Source string // The contents of the erroneous line, without leading or trailing whitespace
+}
+
+func (e ErrSyntax) Error() string {
+	return fmt.Sprintf("invalid INI syntax on line %d: %s", e.Line, e.Source)
+}
+
+// A File represents a parsed INI file.
+type File map[string]Section
+
+// A Section represents a single section of an INI file.
+type Section map[string]string
+
+// Returns a named Section. A Section will be created if one does not already exist for the given name.
+func (f File) Section(name string) Section {
+	section := f[name]
+	if section == nil {
+		section = make(Section)
+		f[name] = section
+	}
+	return section
+}
+
+// Looks up a value for a key in a section and returns that value, along with a boolean result similar to a map lookup.
+func (f File) Get(section, key string) (value string, ok bool) {
+	if s := f[section]; s != nil {
+		value, ok = s[key]
+	}
+	return
+}
+
+// Loads INI data from a reader and stores the data in the File.
+func (f File) Load(in io.Reader) error {
+	bufin, ok := in.(*bufio.Reader)
+	if !ok {
+		bufin = bufio.NewReader(in)
+	}
+	return parseFile(bufin, f)
+}
+
+// Loads INI data from a named file and stores the data in the File.
+func (f File) LoadFile(file string) (err error) {
+	in, err := os.Open(file)
+	if err != nil {
+		return
+	}
+	defer in.Close()
+	return f.Load(in)
+}
+
+func parseFile(in *bufio.Reader, file File) (err error) {
+	section := ""
+	lineNum := 0
+	for done := false; !done; {
+		var line string
+		if line, err = in.ReadString('\n'); err != nil {
+			if err == io.EOF {
+				done = true
+			} else {
+				return
+			}
+		}
+		lineNum++
+		line = strings.TrimSpace(line)
+		if len(line) == 0 {
+			// Skip blank lines
+			continue
+		}
+		if line[0] == ';' || line[0] == '#' {
+			// Skip comments
+			continue
+		}
+
+		if groups := assignRegex.FindStringSubmatch(line); groups != nil {
+			key, val := groups[1], groups[2]
+			key, val = strings.TrimSpace(key), strings.TrimSpace(val)
+			file.Section(section)[key] = val
+		} else if groups := sectionRegex.FindStringSubmatch(line); groups != nil {
+			name := strings.TrimSpace(groups[1])
+			section = name
+			// Create the section if it does not exist
+			file.Section(section)
+		} else {
+			return ErrSyntax{Line: lineNum, Source: line}
+		}
+
+	}
+	return nil
+}
+
+// Loads and returns a File from a reader.
+func Load(in io.Reader) (File, error) {
+	file := make(File)
+	err := file.Load(in)
+	return file, err
+}
+
+// Loads and returns an INI File from a file on disk.
+func LoadFile(filename string) (File, error) {
+	file := make(File)
+	err := file.LoadFile(filename)
+	return file, err
+}