ENH: remove use_keyring argument.
STY: fix too long docstring.
TST: add simple test for username -> auth conversion.
REF: remove most remaining hook mentions.
TST: ensure we bail when hook != False.
BUG: fix test that depended on ~/.enstaller4rc presence.
TST: add test for Enpkg.abort_execution.
ENH: use print as a function in enpkg.py.
TST: add simple test for empty actions.
TST: add more tests for rever_actions.
BUG: fix 2.7-ism.
BUG: test and fix invalid exception catch in revert_actions.
TST: add simple test for 'enpkg --list'.
TST: add 'test' for the importrs_option function.
BUG: fix tests when no .enstaller4rc is setup.
TST: add simple --imports sanity test.
TST: add test for incomplete auth.
TST: add 'functional' tests for enstaller auto-update.
REF: rename _get/_setpassword to highlight keyring aspect of it.
REF: remove obsolete use_keyring.