set default ParticleProperties to (our actual) water properties. #85
add lua script for setting properties of water element. #85
make immutaleProperties setting possible. #85
add script-interface for setting immutable properties. #85
fix passing lambda to LuaWrapper in ParticleScriptAccess. #85
change return type of some functions from int to void. #85

they were int previously because you can't register (void) functions to the LuaWrapper at the moment,
but we don't register the functions directly but via a lambda function which we can set manually to return e.g. int
alter ParticleGroup interface, add first particle lifetime management. #85
change water properties to actual water properties. #85
use uint32_t and glow::Vec3Array as parameters for createParticles. #85
add emit() function to ParticleGroup. #85

* including Observer pattern (thanks @FHorschig for pointing that out to notify every ParticleGroup when 1) visuals should be updated and 2) with the time delta to determine when to emit particles.
enhance particle emitting with random scattering. #85
add gpu acceleration for particles in ParticleGroup. #85
clean up. #85
fix emit scattering. #85
emit particles on left click, stop on release (not following hand). #85
add basic protection against creating particles with out of range index. #85

* has to be enhanced, at the moment the creation simply stops then.
fix array creation by allocating on heap. #85
Merge rework master into management