Merge tag 'v2.13.0' into develop

Release v2.13.0
Added missing release date. Fixes issue #20.
Added "Source Code" section to read-me. Fixes issue #19.
Deleted unused code
Replaces use of UsePasHexSymbol function in UVerUtils.pas to set hex symbol to be used with use of constants that specify either the C or Pascal style hex symbols explicitly.

This change fixes issue #21.
Refactored lookup tables and associated code: extracted common code and types into support routines and types and rationalised the code.
Value names in .vi (ini format) files are now specified using string constants instead of string literals. Existing constants renamed.
Bumped patch version number.
Updated change log with details of release v2.13.1
Merge branch 'release/2.13.1'