Methods for run and pause

Add methods for controlling the state of the app.
Add info to exception

Add uniform number to exception to make it easier to pinpoint the root
cause of an error.
Method to clear current texture parameters

Add method to clear the current texture parameters, this will force the
renderer to set the parameters next fram. Useful for instance when
coming back after context has been lost.
Add method to clear buffers and simplify implementation

New method to clear buffers.
Move implementation of setup to TextureHandler to simplify
implementation.
Set active texture based on index number

Simplify usage of activeTexture by using index number from 0 and upwards
for the texture units.
Bugfix, reset runtime values, new activeTexture usage.

Bugfix, reset runtime values in startRenderer. Without this fix the
wrong values will be used when resuming after pause.
Use new activeTexture method.
New method to delete programs and shaders

Conveniance method to expose functionality to detach and delete shaders
+ programs.
Bugfix Android app-lifecycle, resume() + stop()

Bugfix for Android app resuming, make thread idle until EGL is
recreated.
Call resume() and stop() from Android activity.