added requiresSQLCommentHint true

To make Doctrine schema tool able distinguish between this type and string such that it does not try to update the field every time update schema is run.
Removed unnecessary whitespace.
Added a test for requiresSQLCommentHint()
Regenerated documentation to include the new requiresSQLCommentHint()
Removed minimum stability of "dev" from composer.json
Merge branch 'zerrvox-patch-1'
Updated CHANGELOG and README