Merge lp://qastaging/~mc-return/compiz/compiz.merge-firepaint-improvements into lp://qastaging/compiz/0.9.10

Firepaint, code cleanup:

Declare variables outside of loops.
Declaration and assignment of local variables in one line.
Use pre- instead of postfix increment.
Removed redundant newlines.
Removed redundant casts. (from (float) optionGetFireColor)
Removed redundant brackets.
Added missing break (style issue only).
Added comment and TODO.
Fixed indentation.

Firepaint, speedup:

We just enable GL_BLEND if it is disabled and
we just disable GL_BLEND if it was disabled before.

Introduced the GLfloats xMinusW, xPlusW, yMinusH and
yPlusH to store calculated coordinates instead of
recalculating them multiple times.

Introduced
float fireLife = optionGetFireLife ();,
float fireWidth = optionGetFireSize ();,
float fireHeight = fireWidth * 1.5f; and
bool mystFire = optionGetFireMystical ();
and used those variables inside the loop.

Firepaint, .xml.in cleanup:

Firepaint now has 2 tabs, 'General' and 'Particle Settings'.
The name of this plugin is Firepaint, <short> should not contain
the description.
Better description of the plugin.
Uppercase option titles.
Punctuation for tooltips.
Improved tooltips.

Firepaint, fixes:

Initialize all class member variables in the ParticleSystem::
ParticleSystem () ctor (LP: #1101512, LP: #1101580).

Note/TODO:
Seems that changing the background brightness setting is not really possible (bug #1173789).
Also activating the cube, while firepainting makes the hack to darken the background visible (it is an overlay of two triangles in this case)... -> bug #1198567.