install owslib only on python 2 for now (this will intentionally leads to errors on python 3)
Make OWSLib optional.

The ImportError is deferred until the classes are actually used.
Skip OWSLib tests on Py3.
Add __future__ imports to remaining Python files.

It should be known that these cause no difference since Cartopy has been
tested on Python 3. However, the lack of consistency makes for easily
introduced bugs in the future.
Rename test_pep8.py -> test_coding_standards.py.

Also, add license. Dates determined from git log.
Add coding standards test for __future__ imports.
Merge branch 'python3-__future__' into py3-testing
Merge branch 'owslib-optional' into py3-testing

Conflicts:
	lib/cartopy/tests/mpl/test_web_services.py
add python 3.4 to travis
try removing version restrictions from conda install because they aren't being found for python 3
move pep8 from conda to pip section
move several pure-python packages to pip install
Fix Travis' after_failure script with Python3.
Re-pin matplotlib version.
Test Python 3.3 too.
Temp fix for precision errors.

Python 3 stringifies the floating point number with a different
precision and this causes a difference in all the results.