VCS: Introduce configureable timeout to vcs,svn, p4.

src/plugins/cvs/cvsplugin.cpp

src/plugins/cvs/cvssettings.cpp

src/plugins/cvs/cvssettings.h

src/plugins/cvs/settingspage.cpp

src/plugins/cvs/settingspage.ui

src/plugins/git/settingspage.ui

src/plugins/perforce/perforceplugin.cpp

src/plugins/perforce/perforcesettings.cpp

src/plugins/perforce/perforcesettings.h

src/plugins/perforce/settingspage.cpp

src/plugins/perforce/settingspage.ui

src/plugins/subversion/settingspage.cpp

src/plugins/subversion/settingspage.ui

src/plugins/subversion/subversionplugin.cpp

src/plugins/subversion/subversionsettings.cpp

src/plugins/subversion/subversionsettings.h