New macros added to Standard_Version.hxx to identify OCC version more precisely:

- OCC_VERSION_DEVELOPMENT is to be defined as string in any version different from official release, to indicate that it is modified

- OCC_VERSION_COMPLETE is string form of the complete version number major.minor.maintenance

- OCC_VERSION_STRING_EXT is extended string for of the version equal to OCC_VERSION_COMPLETE and adding OCC_VERSION_DEVELOPMENT as suffix if it is defined

Version promoted to 6.5.3.beta1