Bug 708174 - A text based intent driving tool for GIMP (Tito)
Bug 708174 - Improve the original search dialog patch.

It uses now GIMP preferences. Several preferences removed in favor to
position/size remembered.  Also now action history is tightly tied to
GimpAction and logs all action activation (however it activates), and
the show_unavailable parameter also applies to history.
Finally fix various bugs and improves code design and efficiency.
app: action-search-dialog opacity now changed by ctrl-scroll.
Bug 708174 - various fixes on tito.

Quit button removed.
Do not keep above other windows anymore.
When focus text entry, do not select all.
When list focused and text typed, focus text entry back.
g_markup_escape_text() text which will be used in cell markup.
app: improved algorithm for action search.

Now matches have various levels of reliability.
If the keyword is 2 characters, the match on first letters of first 2
words is most reliable; then a label prefix, then a substring anywhere
in the label; then a substring anywhere in the tooltip; and finally a
fuzzy match. This new algorithm would return the same list as before,
but in a much more significative order.
I also got rid of the " " = show all trick, replaced by a NULL keyword.
app: plug-in-recent-*/repeat/reshow filtered from action search.

plug-in-recent-* should not be historized nor shown, in particular since
they show the same label as the action they repeat and looks like
duplicated actions.
plug-in-repeat/reshow are not historized but are still shown in the list
because they have a different label and are still an interesting search.
Add new action search dialog to POTFILES.in

Fix failing 'make check' by adding app/dialogs/action-search-dialog.c
to /po/POTFILES.in.
Fix tests to handle new action search dialog.

The expected sessionrc must contain action search dialog's settings.
Fix make check.
app: change default value of action-history-size to 100.
app: when hiding the action search action list, unselect any selection
app: action search does not display its own action, and it is not logged either.
app: do not fuzzy-search actions in the history.

Fuzzy search is powerful when you know what you are looking for. But
it can also insert very irrelevant results, and we don't want these as
first answers.
app: remove leading/trailing spaces to keyword before action searching.
app: normalize all texts and make search word-aware.

This allows for instance to return "Gaussian Blur" when searching
"blur gaussian", even though order of words is reversed.
app: add an opacity button to the search dialog to change window opacity