Update major version to 3.2

Code/Mantid/Build/CMake/VersionNumber.cmake

 # Set the version number here for MantidVersion and the package filenames
 
 set ( VERSION_MAJOR 3 )
-set ( VERSION_MINOR 1 )
+set ( VERSION_MINOR 2 )
 
 # UNCOMMENT the next 'set' line to 'force' the patch version number to
 # a value (instead of using the count coming out of 'git describe')