Fix GLSL heat solver after timestep -> timeStep change
Restore WebGL support in Energy2D

51873425
Let user dynamically change WebGL calculations and rendering in Energy2D

52291163

Now it's enough to call:
set('use_WebGL', true) or set('use_WebGL', false)

in console:
model.properties.use_WebGL = true / false

to switch WebGL rendering on / off. Model won't be reset, simulation
will continue from the current point.