Fix edge case where an empty struct could be generated in an ESSL 1.0 shader.
Include _maskThreshold and _doubleSided in ESSL 1.0 shaders.
Add GL_OES_standard_derivatives extension to ESSL 1.0 shaders. According to
gpuinfo.org, this has 96% device coverage and supports both Mali-400 and Adreno
(TM) 304.
Remove 3D sampler support from ESSL 1.0 shaders. This extension is only
supported by 62% of devices.
Change filagui material to a FL0 material.
Eliza Velasquez
f64eef02a3