DNSimple provider (#43)

* Implement a basic DNSimple provider.

Handles domain delegation as well as record create, update, and delete.

Note that this is completely untested at the moment. It’s so alpha it might burn your face off.

* Add some inline comments. Always use the StackExchange libs.

* Clean up dnsimple docs a little

* This will need to be changed before merging.

* Import the dnsimple dnscontrol package from its expected path

* Properly build the FQDN and implement record listing so create/update/delete are used correctly.

* Add support for overriding base URL to allow connection to sandbox.

* Vendor dnsimple-go and its dependencies.

* Remove unnecessary doc file.

* Use dnsutil.AddOrigin for combining record name and origin.

* Modifying dnsimple provider to pass tests

docs/_providers/dnsimple.md

@@ -0,0 +1,38 @@
+---
+name: Dnsimple
+layout: default
+jsId: DNSIMPLE
+---
+# Dnsimple Provider
+
+## Configuration
+
+In your providers config json file you must provide a DNSimple account access token:
+
+{% highlight json %}
+{
+  "dnsimple":{
+    "token": "your-dnsimple-account-access-token"
+  }
+}
+{% endhighlight %}
+
+## Metadata
+
+This provider does not recognize any special metadata fields unique to DNSimple.
+
+## Usage
+
+Example javascript:
+
+{% highlight js %}
+var DNSIMPLE = NewDnsProvider("dnsimple", DNSIMPLE);
+
+D("example.tld", REG_DNSIMPLE, DnsProvider(DNSIMPLE),
+    A("test","1.2.3.4")
+);
+{% endhighlight %}
+
+## Activation
+
+DNSControl depends on a DNSimple account access token.