Remove NetBeans configuration file
Target Java 7 instead of Java 5; bump minor version

Main benefit is the ability to switch on strings, though access to other new APIs is also beneficial.

Stats show that 96% of all servers and 90% of servers currently running this plugin are on Java 7 or higher already.
Refactor command handling, fixing a few minor bugs along the way

Also of note: better colour handling.

More work still needs to be done here, I think, but this is good enough for now.