Fix typos

* PR64:
  Flake8
  Remove type annotation to support python 2
  Allow control over return type of parse_duration.

# Conflicts:
#	src/isodate/isoduration.py

* PR16:
  Don't match garbage characters at the end of time strings
  Don't match garbage characters at the end of date strings
  Factor in some regexes

# Conflicts:
#	src/isodate/isodates.py
#	src/isodate/isotime.py

* PR60:
  Use non-beta Python 3.8 on Travis
  Use Python 3.8 beta on Travis
  PEP8: 79 chars
  Use Xenial on Travis to test on Python3.7
  Fix Python 3.8 DeprecationWarning
  Add support for py37 and py38
  Raise warnings produced by isodate as errors during tests
  Avoid unclosed file warning

# Conflicts:
#	.travis.yml
#	setup.py
#	src/isodate/duration.py
#	src/isodate/tests/__init__.py
#	tox.ini

* PR57:
  remove the license from tests
  1) move license to Project's root 2) add a missing sentence from 2-clause license 3-clause license ("BSD License 2.0", "Revised BSD License", "New BSD License", or "Modified BSD License"): [(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.]

# Conflicts:
#	src/isodate/__init__.py
#	src/isodate/duration.py
#	src/isodate/isodates.py
#	src/isodate/isodatetime.py
#	src/isodate/isoduration.py
#	src/isodate/isoerror.py
#	src/isodate/isotime.py
#	src/isodate/isotzinfo.py
#	src/isodate/tests/__init__.py
#	src/isodate/tests/test_date.py
#	src/isodate/tests/test_datetime.py
#	src/isodate/tests/test_duration.py
#	src/isodate/tests/test_strf.py
#	src/isodate/tests/test_time.py