Cleanup code and use IDocumentation::Ptr everywhere.

Someone willing to do the same for KDevelop code?
Change the behavior of git version check so that it will now acknowledge that git version 2.1.0 is Newer than 1.7. Also a version equal of 1.7 will now not be considered too old.
REVIEW: 120962
Merge branch 'master' of git.kde.org:kdevplatform