Moved out as a standalone tool.

Moved out to join ANDFutils.

TDF 4.1; TenDRA 4.1.2 release.

This is Issue 4.0 of the TDF Specification. TDF version 4.0 is not bitwise compatible with earlier versions. Major changes from issue 3.1 are:

A new SORT for STRING is introduced.

A new EXP constructor, initial_value, is introduced to allow dynamic initialisation of global tags.

Magic numbers are introduced at the start of files containing TDF bitstream information.

The version 3.1 constructor set_stack_limit has had to be modified in the light of experience with platforms with ABIs which require upward-growing stacks or use disjoint frame stacks and alloca stacks.

Various other minor changes have been made to elucidate some rather pathological cases, e.g. make_nof must have at least one element. Also there are some cosmetic changes to improve consistency, e.g. the order of the arguments of token are now consistent with token_definition.