Splitting XML-related stuff to ManiaLib\XML
Updated readme and composer
Removed ManiaLib\XML since it's in maniaplanet/manialib-xml
.gitignore
Added ManiaLib/Manialink/Exception and fixed exceptions other classes
Merge pull request #1 from maniaplanet/manialib-xml-split

ManiaLib\Manialink now depends on ManiaLib\XML