TEST: add stub of testing repository
IMPL: write commits-cache
REFACTOR: split git_parse_commit_line() off

will need it for extending cache
Merge master to dev/commitcache
REFACTOR: nice prototype to retry

say goodbye to top-down source, it's anyway too big
REFACTOR: preparing interface for using commit cache
REFACTOR: move iterate_popen to beginning and make it proper prototype

start making sections
REFACTOR: parse and save at the same time
IMPL PARTIAL: use commits from cache rather than from todo

TODO: resolve missing commits
merge commits-cache
merge testing
REFACTOR: name more appropriately
FIXUP: properly check length
DOC: plan missing etc.
TRY: some sketches about missing commits
Revert "TRY: some sketches about missing commits"

This reverts commit cffdc42fe31a729952dbe1f58c149195554a9b6e.
DOC: describe commits
DOC: describe todo
TRY: stub of test for cmd
TEST: some basic test