GLMixer Code

Cosmetic changes in GUI (About menu entries & user preference dialog)

Enable triggering of switch to session by standard activation of a line
in the Session Switcher (with double clic OR Return / Enter keys).

Hide the cursor during an action (e.g. grag or scale) when it is going
out of the editor window: this way, it is not interfering with the other
windows and programs outside (typically the output window which should
never show a cursor on screen).

Fixed CMake install for Cmake 2.8

Added menu help to open website (sourceforge) and video tutorials
(vimeo)

Added action "Edit" on current source (raise property editor or
ShaderToy code editor)

Updated README and About.

Fix Cmake for compilation with CMAKE 2.8

Added NEW SCALABLE icon of GLMixer (used for debian package)

Fixer argument handling (options must START with '-', not only containt
it)