Add test runner options for flags and environment

This will add the debug runner options to match those in the runner options.
Both runners will also receive support for setting custom environment parameters.
I'll finish this asap and I want to add support for Tools->Go tools->Run go fmt before we can release a beta in the plugin manager.

Preview:
![debug runner arguments](https://f.cloud.github.com/assets/607868/1786990/01b5d626-68fe-11e3-8830-3b38288f0eb0.png)