Added Lines Before Namespace Fixers

NoBlankLinesBeforeNamespaceFixer is a contrib level fixer, and OneBlankLinesBeforeNamespaceFixer is a symfony level fixer. This also includes some utils refactoring and improvements.
I must admit initially i also didnt think about it being designed for docblocks.
`splitLines()` => `splitDocblockLines()` is more descriptive i think

and `splitLines()` => `countDocblockLines()`