Regenerating uniform maps fix

Regenerating uniform maps fix

The problem:
Crash when uniform maps changed on the update side but not on the render side.
The crash is caused if "keep rendering".

The fix:
When new shader is set, the message is sent to Render::Renderer which will be
executed when object becomes visible (renderable). The message sets the flag
indicating whether the shader changed so next time the renderer sets uniforms
first the maps will be regenerated.

Change-Id: I06d872945f1db6c8fe180d347a5674e8931761b7