formatting: Remove segment parts, you can use template tags instead. Segment parts were used to switch formatters insides a given content segment, but that's also achievable with template tags like `pcformat` in Jinja to some degree. It's not totally the same but removing it simplifies the code and improves performance.

cov-core==1.15.0
coverage==4.0.3
invoke==0.12.2
mock==1.0.1
pytest==2.8.7
pytest-cov==2.2.1
pytest-mock==0.10.1