[l10n] Update Japanese translation
Updated Arabic translation
Adjust to Vala 0.18 bindings for GtkTreeStore

The 'remove' method now takes its argument by reference (because it
modifies it to point at the next row after the removed one).

This was changed in https://bugzilla.gnome.org/show_bug.cgi?id=675402

Bump Vala dependency to 0.17.1.15, which is the commit that introduced
the change.

https://bugzilla.gnome.org/show_bug.cgi?id=678665
dist the internal header files

Include baobab-chart.h, baobab-treemap.h, baobab-ringschart.h in
noinst_HEADERS so that they get included in the tarball.

We can't put them in baobab_SOURCES because apparently automake's Vala
support doesn't like that...
Release 3.5.3
Updated Indonesian translation
Updated Telugu Translation
po/vi: import from Damned Lies
Updated Indonesian translation
Added Indonesian translation of User Guide
Added missing file to POTFILES.in
Updated Spanish translation
Updated POTFILES.skip
Updated Traditional Chinese translation(Hong Kong and Taiwan)
Updated Lithuanian translation
Updated Belarusian translation.
Add missing mnemonics

Add missing mnemonics to strings in chart.
Basically I replaced gtk_image_menu_item_new_with_label with
gtk_image_menu_item_new_with_mnemonic and added an _ to do
a mnemonic.

https://bugzilla.gnome.org/show_bug.cgi?id=670670
Updated Spanish translation
Update Chinese translation
Updated Traditional Chinese translation(Hong Kong and Taiwan)
Updated Indonesian translation