Don't let the tagmanager automatically reparse files if they seem to be changed on disk (affects all files in the current session, not the current one). This should speed up file saving a little bit, especially with remote files.
Remove now unnecessary calls to tm_workspace_update().

git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/trunk@3598 ea778897-0a13-0410-b9d1-a72fbfd435f5