* Set three modes of operating serial:
* Default: serials will start at 0 and increment at every change
* Beginning: serial will be set to the value found in the JSON then increment at every change
* Full: serial will be set based on the value found in the JSON at each refresh
* Also fixes a session ID bug where the variable was never random
* Introduces the following flags: `rtr.sessionid`. `rtr.refresh`, `rtr.retry` and `rtr.expire`
Resolves issue #52
* Add SSH support in library.
* GoRTR and RTRdump to use SSH with user/password or without auth
* Updated README with simple compatilibty matrix,
SSH configuration, Cisco configuration.
