* [GRAPH_THEORY,DEB] Added unit test for adjacent_edges(+,+,-) TRUE.
* [GRAPH_THEORY,DEB] Added unit test for adjacent_vertices(+,+,-) TRUE.
* [GRAPH_THEORY,DEB] Added unit test for degree_sequence(+,+) TRUE/FAIL.
* [GRAPH_THEORY,DEB] Added unit test for maximum_degree(+,+) TRUE.
* [GRAPH_THEORY,DEB] Added unit test for minimum_degree(+,+) TRUE.
* [GRAPH_THEORY,NEW] Added regular/1 and unit test (+) TRUE/FAIL.
* [PL_MODE,FIX] Fixed cal_ground_semidet/1: checking for ground arguments.
* [SORT_EXT,FIX] The wrong ordering procedure was applied based on options.