Added thread-safe tasks that will be run by the trema thread.
Added missing header files for Tasks feature.
Merge remote branch 'trema-edge/develop' into merge-threadsafe-tasks
Fixed spelling error and variable name collision.
Readded current_tasks initialization.
Merge branch 'feature-threadsafe-tasks' into merge-threadsafe-tasks
Merge pull request #114 from axsh/merge-threadsafe-tasks

Thread safe task passing to Trema