Added legacy option to webGL renderer (#3630) ...

* Added legacy option to webGL renderer

Setting ```legacy``` to true now forces VertexArrayObjects and
MultiTexture Batching to be disabled. We also store the variable on the
renderer just incase we want to use it to force settings in anything
else.

also added a test

* remove WebGLTests as they don't work on server

* Added extra param to Application

* Adds WebGL test for legacy

* Better check for WebGL in tests