Change obj->oextra->omid from a usually-Null pointer field in
oextra to a simple 'unsigned' that doesn't need any allocation
beyond obj->oextra itself. Value 0 means that it is not in use;
it is used to hold a monst.m_id and those are always non-zero.
Delete unused obj->oextra->olong. 'olong' used to be the last
field in struct obj, put there to force alignment of anything
which followed it back when obj structures were over-allocated to
append extra information. It had a comment about being used for
temporary gold but whatever that was, temporary gold was gone long
before obj->oextra got introduced.
Bump EDITLEVEL since this invalidates existing 3.7 save files.
Remove a bunch of tabs from obj.h and save.c.
e63fed627c