OS X: Fix AttentionBar close button rendering artifact.

Because it's background was set to a solid color, it wasn't rendered
transparently and the gradient didn't show up underneath it.

Fixed by setting the background on Windows only.
Don't include wx/wxprec.h.

Poedit doesn't use precompiled headers, so it only slows compilation
down.
Fix unrealiable warning about missing translator's credentials.

Poedit didn't warn about missing translator name and email if the values
in wxConfig were set to empty strings, rather than missing entirely.
Fixed.
Update Italian translation.
Autodetect available languages in UI language chooser.

Instead of keeping a list of translations compiled it, use the new
wxTranslations API to query them at runtime.

This is both easier to maintain and friendlier to translators: it is now
possible to add a new translation file and test it, without having to
modify the source code.
Use the wxTranslations API if available.

We can use locale-less translations-only API when compiling against
wxWidgets 2.9 (which is how the MSW and OS X binaries are compiled), so
do it.

This makes it possible to support translations that don't have
corresponding locale support in the OS.
Add CFBundleLocalizations to Info.plist.

This is required for Cocoa to understand what localizations there are.
Even though wxWidgets library works without it, e.g. Sparkle won't show
non-English UI unless [one of] the user's preferred language is listed
in CFBundleLocalizations.
Fix failure to save after msgcat failed fatally.

If msgcat didn't create any output file, wxRemoveFile() would fail and
the file wouldn't be saved.
OS X: Fix double separator in the File menu.
Handle app-global menu commands in PoeditApp.

Previously, everything was handled at the PoeditFrame level. This didn't
work well on OS X, where the menu is active even with no windows open.

In fact, Poedit crashed because of this. Set app-global menu on OS X to
avoid this.

Also change the behavior when opening files: in GNOME and OS X, open a
new window, as is the standard behavior. (Unless the active window is
empty, in which case reuse it.)

Fixes #474.
Don't save windows positions on OS X either.

Otherwise multiple open documents would be behind each other, confusing
the user. The OS is smarter about positioning the windows anyway.
wx-2.8 compilation fix.
Use wxFontPickerCtrl for custom fonts.
Revert "don't compile catalogs into .mo files when saving by default".

This change was causing problems to people not familiar with Poedit, who
followed one of the many tutorials that don't mention this setting, yet
assume the creation of MO files. See e.g.
https://groups.google.com/d/topic/poedit/Coza58B1jQQ/discussion

This change will be re-introduced later, probably for 1.6, but together
with better UI to avoid this kind of confusion. At the very least, there
needs to be explicit "Compile to MO" menu entry before the default can
be changed.

This reverts d0648c95d6a45b37950f1e388a00b8519f806796 commit.
Update wxWidgets to a version with fix for bad wxListCtrl rendering.

Fixes #479.
Update Italian translation.

Fix some other typos.
Revert "Remove line numbers from the UI."

Leaving nontrivial UI changes like this for 1.6.

This reverts commit c6bbdfd953ad6e8b682faa7f5bd2934dc0be5bfe.
Ask for donations, Transmission-style.

At most once a week a popup asking for donations is shown. The user can
dismiss it forever by checking the "Don't bug me about this again"
checkbox to minimize obtrusiveness.
Correctly choose default UI language.

Choose it based on language settings, not locale.
Remove outdated comment.