Stable release with new timeout function

• fixing a few typos
• adding system function with timeout possibility
  (useful for research in computer engineering where
  generated code may be buggy and result in infinite loops,
  i.e. during autotuning or compiler testing and bug detection)
• ck where repo: will print URL for remote repositories
  (suggested by Anton)
• making text to select UIDs less ambiguous (asked by Anton)
• fixing bug in flatten_dict while working with CLSmith
• changing COPYRIGHT to COPYRIGHT.txt and LICENSE to LICENSE.txt