Some pycodestyle (PEP8) fixes

See merge request !746

Tristan Van Berkom authored Aug 28, 2018 and Tristan Van Berkom committed Aug 29, 2018

This adds a step to the docs generation Makefile to generate
release.svg and snapshot.svg badges, modelled after the gitlab
badges.

This also adds the generated badges directory in docs to .gitignore

Tristan Van Berkom authored Aug 28, 2018 and Tristan Van Berkom committed Aug 29, 2018

This is a part of #528

Tristan Van Berkom authored Aug 28, 2018 and Tristan Van Berkom committed Aug 29, 2018

This is a part of #528

Release badges

See merge request !742

Add a helper function assert_ref_in_track to git.py GitMirror()
which is used when staging & initing the source workspace. It
checks the element's ref exists in the track (branch/tag) if it
has been specified, raising a warning if necessary. The warning makes
use of the warning token 'REF_NOT_IN_TRACK' from the configurable
CoreWarnings. If the element has been tracked with bst, it is assumed
that the value of ref exists in the track as it was generated from it
& as such is not asserted.

Add tests that cover assert_ref_in_track & the configurable
CoreWarnings REF_NOT_IN_TRACK warnings token.