SL-19147 Water quality pass.  Remove gl_FragDepth writes from sky rendering (optimization).  Incidental decruft.

Get dome rendering to not assert the depth test state behind deferred render's back.

Make clouds write and test depth to give stars something to depth test against.

Add z-bias in star vert shader to force some depth testing of stars against clouds.

SH-1682 Dynamically adjust the number of texture channels to use for indexed texture rendering based on available hardware.

See https://wiki.lindenlab.com/wiki/License_Substitution for details.

Self reviewed.

Merge of QAR-1267 to trunk.  This was a combo merge of QAR-1175 (maint-render-9) and QAR-1236 (dll-msvcrt-2)

svn merge -r 109838:112264 svn+ssh://svn.lindenlab.com/svn/linden/branches/maint-render/maint-render-9-merge-r109833

QAR-389