Merge updated git-gui and gitk that call each other

Merge git://repo.or.cz/git-gui and git://git.kernel.org/pub/scm/gitk/gitk * git://repo.or.cz/git-gui: git-gui: Show special diffs for complex conflict cases. git-gui: Make F5 reselect a diff, if an untracked file is selected. git-gui: Reimplement and enhance auto-selection of diffs. git-gui: Support conflict states _U & UT. git-gui: Support more merge tools. git-gui: Don't allow staging files with conflicts. git-gui: Support calling merge tools. git-gui: Support resolving conflicts via the diff context menu. git-gui: Mark forgotten strings for translation. git-gui: Allow specifying an initial line for git gui blame. git-gui: Better positioning in Blame Parent Commit git-gui: Support passing blame to a parent commit. git-gui: Support starting gitk from Gui Blame git-gui: Teach git gui about file type changes * git://git.kernel.org/pub/scm/gitk/gitk: gitk: Add menu item for calling git gui blame gitk: Add option to specify the default commit on command line