Centralise release version numbers in one file

[delphidabbler]

At present, file and product release version numbers are common to both the standard and portable editions of CodeSnip, but they have to be entered separately in VCodeSnip.vi and VCodeSnipPortable.vi.

This leaves room for error.

So create a new VERSION file that contains versions and include those values in the .vi files as macros.

[delphidabbler]

Actually extracted some common string file info into macros too.

Named macro file VersionInfo.vi-inc instead of VERSION.