Windows compatiblity - pwd vs cwd

[braintapper]

process.env.PWD doesn't work on Windows and generates an error when trying to load fogbugz.conf.json. Using process.cwd() on Windows by changing line 44 in index.js to fixed it for me:

conf = require(path.join(process.env.PWD || process.cwd(), 'fogbugz.conf.json')),

[boneskull]

@braintapper can you send a PR?

[braintapper]

Sorry, I didn't fork your repo, I simply manually edited my node_modules folder in my project to see what the root cause was (yeah, bad practice, I know).