Fix for #275.
Merge pull request #276 from DLu/is_current_fix

Fix for #275.
sets costmap_ to NULL to avoid double free
Merge pull request #277 from efernandez/fix_costmap2d_resize_memory_leak

Fix double free corruption in Costmap2D
adding lock to planner makePlan fail case
Merge pull request #281 from phil0stine/move-base-lock

adding lock to planner makePlan fail case