64Bit support

NOTE the included tesseract/leptonica .dlls are built with VS2012 and will require the VC++ 2012 runtime to be installed. The runtime install can be downloaded here: http://www.microsoft.com/en-us/download/details.aspx?id=30679

The only issue I've encountered is the TessApi.GetVersion() call fails for some reason.

Changes:
Changed the interop code to the appropriate architecture dll to match the hosting process architecture.
Removed x86 and added AnyCPU to the Tesseract managed dll. Having architecture specific builds for dlls isn't necessary since the bitness is determined by the hosting process.
Added x64 and AnyCPU configurations to BaseApiTester and the unit test assembly.