[PROPOSAL] Support multiple JIRAS

This is just a sketch of getting multiple JIRA instance support (#19). I used jirasoap because jirarest doesn't seem to work (it just dumps a python dict to the search page). I'd be willing to enhance that one too if we get past proposal here.

Quite simply, I replaced the config.ini with config.json so that you can define multiple servers, and a default. The syntax becomes `jirasoap mode [instance] options`

The version bump would be major because the switch on config is non-passive.

* Teach jirasoap to search from one of multiple JIRA servers
* load config from JSON instead of an INI