Highlighting definition files: round version up to next integer

Ideally, the version attribute should have been a integer revision
right form the beginning. The problem with the string-based variant
is that it is unclear whether e.g. version "1.1" < "1.10", and some
people even introduce more minor versions such as 1.10.1 etc.

Simply using an integer will solve this problem. For now, KTextEditor
supports the old behavior for compatibility, though. We will evaluate
a final change for KDE Frameworks 6 again.