Update project files to use openbr C++ API

The C++ API defined in opengr_plugin.h is substantially more useful than
the c API, however to use it we need to link some QtLibraries (at least
Qt5Core.lib), and opnencv libraries as needed.
Also, need to include the relevant headers, and update include
directories.

OpenBR code is segregated in br_interface.cpp so that I can #undef min,
since well that is not exactly a harmless macro.

Project files were not updated in a general way (too many hardcoded
paths). Also, currently getting a heap corruption error that makes no
particular sense. Suspect I have an incompatible header/lib set
somewhere.
Add opencv and qt include/lib files, update openbr lib
Preliminary hooks for automatic facial component detection

Debug mode is quite screwed for some reason
And then, Poisson_Multigrid was a static library
But not in release mode, until now
Preliminary hooks for integration with linear solver
Add missing header file
add missing opencv.lib files
Add missing qt .lib files
Don't use absolute paths
Give path to openbr directory relative to .exe location
Merge pull request #7 from caotto/link_update

Update project files to use openbr C++ API