Synchronize (and tidy up?) content of spell.txt
Angband/64 has different spells to Vanilla Angband and also includes different data items in the spell information file.
* Ticket #15754 Implement Angband/64 style spell pages/books
Still to do:
Changes made so far ...
* I: line data from /64 now used instead of the Vanilla Angband format data.
* Spells now have 'spell flag' to be used in code. (e.g. "Magic Missile" has the flag "MAGIC_MISSILE" and would be defined like "#define SPELL_MAGIC_MISSILE 64".
* Spells now in alphabetical order by spell flag.
* Spell pages now in alphabetical order by spell flag.
* Spell index and sval are identical. Both start from 0 and go to 120 in the same order as the records are listed (alphabetical).
* Fill in missing D: lines.
* Make other lines 'live' instead of commented out (will require code changes).