LowercaseConstantsFixer - rewrite to handle new test cases

LowercaseConstantsFixer - rewrite to handle new test cases.
Resolves #793.

May not work on php 5.3 yet
I think we should do this for a 2.0 release?

Should we create an issue where people can throw in ideas for 2.0?

As @keradus said, we don't need a 2.0 release in the near future. @keradus How does having a 2.0 release in about 6 month's time sound if we've built up a decent todo list?