If left kid was in heap but right was not, left kid was ignored.

darcs-hash:20070723151422-65a35-e4a50c9195ebb150b587043dcd4c44c1cc1ed941.gz

darcs-hash:20070713163844-65a35-509a6b4df8e13b039fbbc44bc368e026f3a4e8eb.gz

darcs-hash:20070704225520-65a35-fbdca27efd42285f8b7faa7562df000ff141e9c1.gz

Removed internal files from doxygen-generated documentation.

darcs-hash:20070920173656-65a35-ddd22b107b84ee52fdb9ec536caf5d0c658f864c.gz

darcs-hash:20070704094233-65a35-fcf28389f363e82f0cf5816f96ec294b0906405d.gz

Reduced average number of comparisons and assignments when removing an
entry. Improved tests.

darcs-hash:20070703112744-65a35-64852a7e7fbf38b4a11e8af70d481721259e8ff2.gz

darcs-hash:20070702150206-65a35-d69eddcc83d8c27d2c688de04dbc4f201dfdbb05.gz