tidied tests
Changes to database schema
Updates #8:

Removes --files option. Combines dbbot/command_line_options.py to
dbbot/reader/reader_options.py.

Enhances tests relating to command line arguments

Documentation still needs to be done.
remove unused import
only parse keywords from ExecutionResult if we are going to put them in db
tidied up tests more
reformatted README to adhere to 78 characters per line