colors: start a basic utility lib about colors (to cont)
fix doc warning
fix syntax error
particles: add ParticleInfo0s to store additional info about particles + a proto2d function to display some of this info (color, radius)
emitter: add initializers (particlesAddComponents, addParticleInfo0s, particlesStartPositionPrevious, particlesStartPosition), ...
demos: fix bug (memory leak) when play a new demo, prepare the quadtree demo
emitter: particule + verlet can use the rotation of emitter
proto2d: fix bug if there is no particles
verlet: fix warning in makeCloth
colors: irgb => irgba
demo: particles with colors and opacity animated
colors: optimisation on irgba_ add functions (hsl_triad, ...)