View3D: Handle un-weighed vertex color properly

D608 by Gaia Clary
PoseLib: New pose library actions now have their "id root" setting initialised properly
Style cleanups here
Bugfix for Elastic and Back easing types

** TO BE PORTED BACK TO 2.71 **

As pointed out by Thomas Beck (plasmasolutions), the current behaviour and/or
default values for their parameters didn't quite make sense:

1) Back Easing - The old default value of 0.0 results in some overshoot being applied,
while trying to tweak it up or down resulted in some odd jumps and discontinities.

I've ended up removing some code here which forcibly using a "back" value of 1.7
when users wanted 0.0 instead. There doesn't seem to be any good reason for this.
To ensure that there is still an effect initially, keyframes now get created
with back set to 1.7


2) Elastic Easing - The old default settings of <amplitude = 0, period = 0> resulted
in a curve without any elastic bounce, which wasn't very useful for motion graphics.

Now, default values of amplitude = 0.8 and period = 4.1 get set. These were hand picked
by Thomas to work well when the duration of the motion is 10 frames long (i.e. the
typical length of such effects when doing motion graphics).
Add a bmesh_core_test, a start at testing bmesh functionality.

Needed to make the blender link libraries a global property
now that tests are parallel to source directory.
Current sort order for blender link libraries doesn't work
for tests that start with few defined symbols. Doubling the
lib list works, but a TODO to find a better way (probably
using CMake's own mechanism for tracking dependencies).
Python: Remove deprecated uses of os.popen

T40415 by Lawrence D'Oliveiro
RNA: Expose hook centre

D529 by Gottfried Hofmann
Cycles: Make Volume Bounces default to 0. This is quiet a bit faster, and produces less noise.
updated tooltips based on plyczkowski's design
updated tooltips
updated tooltip design
update tooltip design
update tooltip design
update tooltip design
update tooltip design
add bold font
update tooltip design with bold workaround
update tooltip design without bold
update tooltip design without bold font
remove unneeded files