LowercaseKeywordsFixer - __HALT_COMPILER must not be lowercased
bug #754 LowercaseKeywordsFixer - __HALT_COMPILER must not be lowercased (keradus)

This PR was merged into the 1.2-dev branch.

Discussion
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LowercaseKeywordsFixer - __HALT_COMPILER must not be lowercased

When __HALT_COMPILER is lowercase then PHP produce an error:
```
PharException: internal corruption of phar "foo.phar" (__HALT_COMPILER(); not found)
```

So we should stop lowercasing it.

Commits
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7980c3d LowercaseKeywordsFixer - __HALT_COMPILER must not be lowercased