Brush tool : Replace Gtk::Table (deprecated gtk container)

* Gtk::Box as main container
* Gtk::Grid for brushes container
Brush tool : Replace ToggleButton by RadioButton

All the brushs can now be selected by RadioButton holded by a unique group. So only one brush can be selected at the same time.
Brush tool : Fix 605 - Brush do nothing without image layer

If not image found, add one.
Brush Tool : #615 - Brush tool do not (always) used selected color

Fix rgb to hsv conversion
Linux build: Fix permission issue for deb packages
Merge https://github.com/synfig/synfig
Update Linux build script for Ubuntu 14.10
Glib 2.42 fixes : Parameters are not editable

I was "force" to add a preprocessor directive due to glib changes...

Saying that, now we must build and ship for OS coming with glib >= 2.42
Fix glib version condition
Fix #715: Glib 2.42 issue for keyframes list. Thanks to Ron Bentley.

See http://www.synfig.org/issues/thebuggenie/synfig/issues/715
Always use "By Layer Default" blend method on startup.

This allows to avoid the confusions when (nebbie) user accidentaly changes the default blend method to something like "Divide". In this case the user will be wondering why nothing appears on the scren when he creates something. With this change the blend method will be reset to default value when application is restarted.
Use pixels as default unit of measurement (closes #710)

http://www.synfig.org/issues/thebuggenie/synfig/issues/710
Use "Frames" as default time format
Linux build: Add GTK3 support for packaging script
Win32 build: Use Gtk3
Fix incomplete interface localization in Windows build
Missing Translation

N_() seems to be not expended inside ACTION_LAYERSxxxx definition
Brush tool : Autoresizable Brush chooser as Gtk::ToolPalette

* Remplace Gtk::Box by Gtk::Grid as main container (Gtk::Grid is a new widget that'll replace Gtk::Box)
* Remplace Gtk::Grid by Gtk::ToolPalette for brushes container
* Remplace Gtk::RadioButton by Gtk::RadioToolButton
ToolBox : Propagate Scroll Event from Palette

Make the Tool Palette scrollable from inside the palette not just from the scrollbar
Brush tool : Replace RadioToolButton by ToggleToolButton

Active brush was no-efficient + constitency ui with ToolBox

* Convert all RadioToolButton ref to ToggleToolButton
* Remove unuseful Gtk::RadioToolButton::Group references
* Use of StateBrush_Context::selected_brush_button to track previous selected brush