Merge branch 'ab/config-multi-and-nonbool'

Assorted config API updates. * ab/config-multi-and-nonbool: for-each-repo: with bad config, don't conflate <path> and <cmd> config API: add "string" version of *_value_multi(), fix segfaults config API users: test for *_get_value_multi() segfaults for-each-repo: error on bad --config config API: have *_multi() return an "int" and take a "dest" versioncmp.c: refactor config reading next commit config API: add and use a "git_config_get()" family of functions config tests: add "NULL" tests for *_get_value_multi() config tests: cover blind spots in git_die_config() tests