LowercaseConstantsFixer - rewrite to handle new test cases

LowercaseConstantsFixer - rewrite to handle new test cases.
Resolves #793.

May not work on php 5.3 yet
Yeh, I was aware of how hacky it was. We need a reliable way to skip files when running php 5.3 that contain 5.4 syntax.

I know that if we have the linter enabled, that will obviously prevent bad changes like this, but people may not have the linter enabled.