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 know that if we have the linter enabled, that will obviously prevent bad changes like this, but people may not have the linter enabled.

Then, the linter is enabled by default. One must disabled it in `.php_cs`, then he need to know what and how to do, so let's assume they know problems on linting 5.4 code when running tool on 5.3.


> Deprecate support for PHP 5.3, which is already EOL.

I am not using 5.3 anywhere. Nevertheless we should not throw away support for it.
* many folks are still using 5.3. that is sad, but it's cool to pleasure they
* currently, we DO supoort `T_YIELD`. It's introduced in 5.5. So, you say we should drop support for 5.4 as well? It is the same situation ;)


> I think we should do this for a 2.0 release?

Do what? drop 5.3? I am against for that assumption - we don't know when we will release 2.0. Maybe we will, maybe we won't ;)


> Should we create an issue where people can throw in ideas for 2.0?
What is a benefit of one issue with list of many ideas vs multiple issues tagged in milestone 2.0 ?
I don't say no, both are great for me.


> How does having a 2.0 release in about 6 month's time sound if we've built up a decent todo list?

I am against it. We will release 2.0 when we will need to break BC. It is irrelevant if this will be after 6 months from now or not.