Add VR display auto-calibration logic
Add VR display auto-calibration user message calculations
Make overlays accessible from C++ code
Add some property setters to the billboard overlay
Display a static billboard prompting user to hold still to calibrate HMD
Fix avatar rotation erroneously initiating HMD calibration
Delete calibration message if exit VR display while calibrating
Fix header declaration
backup current work on TextRenderer
Make calibration message update its location more often
first cut at correct handle hide/show behavior and rotate overlay hide/show behavior
correctly reselect entity after property edits to make sure handles move if dimensions or position changes
fix property edit dialog box
display current pitch/yaw/roll in rotation overlays
implement basic support for planar overlay type intersections
work on intersection with rotation overlays
Improve the TextRenderer::draw(), first step

- Introduce a managed Buffer for data to be used on the GPU. THis is the first type of resource (second will be texture) that we plan to    use in the graphics engine in the long term. this is an api agnostic replacement to QGLBuggerObject
  It's in the new file gpu/Resource.h(.cpp)

- Add two gpu::Buffers in the TextRenderer that collect all the glyph vertices (coords + texcoords + color) during the for loop on the string characters of the TextRenderer::draw(). Right now the text glyphs are then drawn in one draw call (and not one per character) at the end of the function.

THe step 2 plan is to keep on collecting all the glyphs from all the TextRenderer::Draw() issued during one frame and to draw all of them in a single drawcall. We decided to split the task in 2 so it's easier to review.
Fixing unix file format issues with msdev2010
Fixing include filename case
Fixing const usage on a template function