Fixed a bug in 3D SpaceMap about check if neighbour location accessable.
Fixed a bug in pathfinder about checkNeighbourAccessable
Fixed bugs for selecting adjacent accessiable neighbour locations.
Fixing loop precondition dependency problem.
Solved precondition loop dependency problem.
Fixed a bug for checking loop denpendency.
Fixed a bug in 3D spacemap for finding neighbour BlockeEntities.
Modified the data struct of ParamCandidate
Fixed sorting the order for groups of non-numeric variable value candidates according to calculate precond and effect fitness.
Merge https://github.com/opencog/opencog into planner
Merge pull request #407 from shujingke/planner

Finished Planner debug.