Adding a vcxproj Tool

This tool contains:
* A new 'MBGenVcxproj' Builder which generates a vcxproj file based on the scons environment and the list of sources
* A new 'MBBuildVcxproj' Method which runs the generated vcxproj (moved from mb_install)
* A variety of Methods for setting up the environment correctly
Correctly add compiler flags in generated vcxproj
Improve formatting of generated vcxproj
Fix project references in generated vcxproj
Pass the location of the repo root to the msbuild script
Now that we're passing in MBRepoRoot to the generated vcxproj, we can use that to find mb_msvc common.
Removing old, unused mb_mingw tool
Breaking mb_install into two tools: mb_install and common
common now check to see if it's being loaded multiple times
Making boost dependency an explicit thing that must be set.
don't always look for boost
Cleaning up mb_install to make it more consistent & readable.
Moving glob into common
Making some comments a little more pythonic
switching from --devel-libs to --no-devel-libs

the common case at this point is to build with devel libs on
the only place we want it off is in the build system
make the vcxproj depend on the vcxproj tool + slight refactor to make that easier
Making some of the commenting more pythonic
Enabling direct-ish property passing from scons command line to msbuild
Tweaking some headers
Forgot to test it without command line options