Fix vendor kwarg handling
Merge pull request #194 from rhattersley/fix-wmts-vendor-kwargs

Fix WMTS vendor kwarg handling
Add vendor-kwargs to WMTS constructor.
Merge pull request #195 from rhattersley/wmts-constructor-vendor-kwargs

Add vendor-kwargs to WMTS constructor.
PEP 8 driven changes to wmts.py.
Merge pull request #196 from rhattersley/pep8-wmts

PEP 8 driven changes to wmts.py.
fix WFS tests