Fixed errors with caching, readability checking, and copying.
fix list copy test

fix list copy test
more unit tests for course

more unit tests for course
Improved in_list().
Merge remote-tracking branch 'origin/back-end-working' into back-end-working
Improved support for timeframes and messages.
Preemptively fixed an error in set_timeframe().
Improved timeframe support.
Fixed a caching bug.
Corrected behaviors of UserEntry.get_word_X() and UserEntry.set_word_X().
Minor change in error handling and reporting.