Try adding support for ARB_instanced_arrays

Convert the colors array back to unsigned char, try adding support
for ARB_instanced_arays. Fix up wireframe and picking for when
the fast path is being used. Previously that would fail.

Change-Id: Iada6b55f01ca7f2c3f68362f3e7da7e99fa15eeb
FIX: Set the hue range for the default lookup table.

The old lookup table would not show up anything on the screen.

Change-Id: I9eabbdc0b7e218e2ac9979d132549a6a647b8f32
Handle case with no lights on

With no lights we drop back to a shader that does not do lighting
equations, much like the 2D maper does by default. New valid image is
a 3D scene rendered without any lighting applied. Different than
the old backend which would still apply lighting equations just with
no lights. If you really want to generate that old style image, create a
light and set its color to black, or intensity to zero, etc. Having a
light that is on will cause the lighting equations to be used even if it
is black  (ZOMG you could have a black light)

Change-Id: I7a8aed9dd060b27528ab5746c4a0d2f3dfaa360a
Merge topic 'try_glyph_extension' into master

23ceef01 Try adding support for ARB_instanced_arrays
Restore test deps for matplotlib tests

These are needed for the tests, fix compilation errors seen on the
default OpenGL dashboards.

Change-Id: Ic8b761cb8ad553f96a32cf29673ce4d9a0757d0f
Merge topic 'pv-plot-bar-lut' into master

bf8a001b FIX: Set the hue range for the default lookup table.
Merge topic 'fix-matplotlib' into master

3ae161f7 Restore test deps for matplotlib tests
Disable some widget tests building for OpenGL2

A few of the volume rendering classes are currently excluded when
building the OpenGL2 backend, these should be restored once this
changes.

Change-Id: I35fcb41313639c23c08033ffa6d19703430d1e37
Merge topic 'widget-volume-gl2' into master

9b17ebdd Disable some widget tests building for OpenGL2
Merge topic 'address_no_lights_on' into master

27f77f8c Handle case with no lights on
Remove extra call to set the divisor

Trivial change

Change-Id: I776b49dc44632715e0da3472d8df3456251a9a4b
Merge topic 'fix_divisor_issue' into master

4233190c Remove extra call to set the divisor
Forgot to add the image hash

Change-Id: I95a9682e398e0561271e369bccf83cb7199540b0
Merge topic 'forgot_image' into master

b26e4d5c Forgot to add the image hash
Replace some valid images lost with the big merge and a pick bug

Some valid images were lost when we merged the github branch way back.
Put those back in and also fix a glyph picking bug.

Change-Id: I003c8485a1dc8ff83b9f2d0f9f69244d150a0ddc
Merge topic 'restore_lost_baselines_and_fix_bug' into master

8cb239bb Replace some valid images lost with the big merge and a pick bug