docs/vcs_support: add information on importing repositories This change directly relates to issue #254. Some rework of the original patch done by Thomas De Schampheleire: - generalize to cover both Mercurial and Git - simplify instructions for importing via filesystem: don't impose a certain flow as it depends on different factors: are the repos already present on the machine, are they organized in a flat hierarchy or already in a more complex one, ... - invalidating cache while rescanning should not be needed when adding new repositories

[pytest]
# only look for tests in kallithea/tests
python_files = kallithea/tests/**/test_*.py
addopts =
    # --verbose
    # show extra test summary info as specified by chars (f)ailed, (E)error, (s)skipped, (x)failed, (X)passed, (w)warnings.
    -rfEsxXw
    # Shorter scrollbacks; less stuff to scroll through
    --tb=short