Tidy up DEBUG macro
NOINLINE only on supported compilers.
More comments from freelist branch.
Moer comments/tidy-ups
More formatting fixes.
Merge branch 'master' into freelists
More comments from freelists.
Merge branch 'master' into freelists

Conflicts:
	lmdb/cpython.c
More formatting fixes
Document IterObject.
More struct comments from freelists branch
Merge branch 'master' into freelists

Conflicts:
	lmdb/cpython.c
Accept but ignore max_spare_* (matches cffi).
Merge branch 'master' into freelists
Updated env_copy from freelists branch
Merge branch 'master' into freelists
Implement Environment.copyfd().
Merge branch 'master' into freelists