Added additional flags and created new function

Added a flag for deleting files after they are copied and also two
flags, one for creating a log of all files that are copied, and another
for deleting those files in that log. These flags are NOT yet
implemented.

Also took out a bunch of the code in main and made it a separate
function.
Added ability to copy videos, moved open logfile

Videos are added to date directories based on when their metadata was
last modified.

The log file is now opened within side_effects_copy... instead of being
opened outside and having it passed into the function.
Added new test case for copying

Added new test case which checks copying of pictures with no flags under
side_effects_copy_file_with_flags.