add missing docs for cxEmptyMap

fix wrong docs for cx_stream_copy()

add missing docs for cx_invoke_destructor()

update Doxyfile to Doxygen 1.9.6

fix const-ness of non-mutating iterator creation for maps

simplify map class structure

fix inconsistent destructor requirements for list and map classes

fix rehash not valid for non-hash-maps

(0) -300 -100 -30 -10 -8 +8 +10 +30 +100 +300 tip

mercurial