Clean up shader-varying-packing-restrictions.html

Fix typos, clarify a few comments and remove dead code.
Backport shader-varying-packing-restrictions.html cleanup to 1.0.2

This fix does not change test behavior.
Merge pull request #351 from NVIDIA/varying-cleanup

Clean up shader-varying-packing-restrictions.html
Fixed https://www.khronos.org/bugzilla/show_bug.cgi?id=950 : Typo in test

Applied patch from Lane Roberts fixing typo.
Merge pull request #355 from kenrussell/premult

Fixed https://www.khronos.org/bugzilla/show_bug.cgi?id=950 : Typo in tes...
Fixed https://www.khronos.org/bugzilla/show_bug.cgi?id=951 : Incorrect setting of UNPACK_COLORSPACE_CONVERSION_WEBGL in premultiplyalpha-test.html?

Changed setting of parameter from false to gl.NONE.
Merge pull request #356 from kenrussell/colorspace

Fixed https://www.khronos.org/bugzilla/show_bug.cgi?id=951 : Incorrect s...
Move 1.0.x latest spec into a subdirectory.

Once WebGL 2.0 exists, we'll have latest/2.0 and latest/1.0. For now
add a redirect from latest/ into latest/1.0.
Fix relative links to ../../../resources.
Merge pull request #357 from grorg/webgl2-move-1.0-spec

Move 1.0.x latest spec into a subdirectory.
Add a test to guard against ANGLE literal overflow handling bug.
Fix an tiny bug.
Fix
Merge pull request #360 from zhenyao/overflow

Add a test to guard against ANGLE literal overflow handling bug.
float_literal.vert.html should not test about missing gl_Position.
Add two extra tests to cover that:
empty_main.vert.html
gl_position_unset.vert.html
Update 00_test_list.txt
Merge pull request #361 from zhenyao/fix

Test about unwritten gl_Position in vertex shaders.
Fixed link to IDL; also updated link to latest and current spec in editor's draft.
Merge pull request #362 from kenrussell/idl-link

Fixed link to IDL; also updated link to latest and current spec in edito...
Specifically ignore stdio for browser sub-process to prevent hangs from filling the stdout buffer. Fixes problem seen with node.js v0.10.18 on Mac OS X.