(Reuses existing strings).

Backport changes applied upstream not to hard-code auto-completion popup
frame border size.

Don't assume changing the style inside a style-set handler results in
recursion, as it would be wrong if the next signal emission was
triggered asynchronously.  Instead, only modify the style if it isn't
already as we want it.

This fixes the about dialog's style-set handlers on GTK 3.10 which
didn't liked constant style updating.

This reverts commit ec707106.

Apparently the selected state of an event box doesn't necessary mean it
will be styled with a selection background color.  This e.g. isn't the
case in GTK 3.14's Adwaita (default) theme.

So, revert the commit that removed custom style overrides.  Next commit
will fix the GTK 3.10 problem this reverted commit fixed.

Useful for when using, for example, GTK+, SDL, and other C-only APIs
in files with the C++ filetype. Before only the symbol auto-completion
worked, but not the highlighting of type names.

TODO: figure out why taking something like SDL.c.tags and making a copy
as SDL.cpp.tags doesn't work, once that's fixed, this extra condition
could probably be removed.

Backport changes applied upstream to fix auto-completion popup sizing.

Backport patches applied upstream to cache auto-completion windows,
hopefully avoiding dead popup windows lying around on GTK3 builds in
some high stress scenarios.

Update of Russian translation

Save As on an empty document would cause warnings like:
sys:1: Warning: g_regex_match_full: assertion 'string != NULL' failed
because SCI_GETRANGEPOINTER returns NULL then.
On a Ubuntu 12.04 system this warning even crashed Geany at writing the
log message.
So, simply don't search for anything if the document is empty.

Backport patches applied upstream to cache auto-completion windows,
hopefully avoiding dead popup windows lying around on GTK3 builds in
some high stress scenarios.

Only cache the popup window itself and not its content, as it seems the
window sizing is affected whether the content was just created or not.

This avoids creating and destroying windows quickly under stress, which
may lead to XID collisions.

See e.g. https://bugzilla.gnome.org/show_bug.cgi?id=581526 and
https://bugzilla.gnome.org/show_bug.cgi?id=590690

Closes [scintilla:bugs:1649].

Allow user to edit open dialog filename when file doesn't exist

This should be cleaner and safer than using '../' mixed with os.chdir().

This enables proper logging when checking for rst2html during configuration.

This is cleaner than searching for rst2html and rst2html.py since Waf
offers the API for this and this change enables Windows support.
While at it, add binary name 'rst2html2' for ArchLinux support.

This is an improvement as requested in #322 to update the HTML docs
after geany.txt or geany.css have changed.
Also, with this change the resulting HTML will be generated in the outdir,
not in srcdir/doc anymore.

Closes PR#324.