VCS[git]: Add support for stashes.

Add non-modal stash management dialog and additional menu option
"Stash snapshot..." to stash away changes prompting for a description,
which will immediately replay the stash (take snapshot and continue
working).
Add interface to IVersionControl for creating/restoring/deleting
snapshots for backup/complex undo operations (currently supported
by git only). Add test options to VCSBasePlugin.
Clean up and extend git client accordingly.

src/plugins/git/git.pro

@@ -22,7 +22,9 @@ HEADERS += gitplugin.h \
     branchmodel.h \
     gitcommand.h \
     clonewizard.h \
-    clonewizardpage.h
+    clonewizardpage.h \
+    stashdialog.h \
+    gitutils.h
 SOURCES += gitplugin.cpp \
     gitclient.cpp \
     changeselectiondialog.cpp \
@@ -38,11 +40,13 @@ SOURCES += gitplugin.cpp \
     branchmodel.cpp \
     gitcommand.cpp \
     clonewizard.cpp \
-    clonewizardpage.cpp
+    clonewizardpage.cpp \
+    stashdialog.cpp \
+    gitutils.cpp
 FORMS += changeselectiondialog.ui \
     settingspage.ui \
     gitsubmitpanel.ui \
-    branchdialog.ui
-
+    branchdialog.ui \
+    stashdialog.ui
 OTHER_FILES += ScmGit.pluginspec
 include(gitorious/gitorious.pri)