General robustness patch from James Harvey:
- most game_size() functions now work in doubles internally and
round to nearest, meaning that they have less tendency to try to
alter a size they returned happily from a previous call
- couple of fiddly fixes (memory leaks, precautionary casts in
printf argument lists)
- midend_deserialise() now constructs an appropriate drawstate,
which I can't think how I overlooked myself since I _thought_ I
went through the entire midend structure field by field!
git-svn-id: svn://svn.tartarus.org/sgt/puzzles@6041
cda61777-01e9-0310-a592-
d414129be87e