removed `pwnlib.log.done_*`
updated pwnlib/data/useragents/download-useragents.py to not use `pwnlib.log.done_success()`
updated `pwnlib.ui.pause()` to not use `pwnlib.log.done_success()`
updated `pwnlib.util.proc.wait_for_debugger()` to not use `pwnlib.log.done_success()`
Merge pull request #257 from Gallopsled/log-remove-done-functions

Gets rid of `pwnlib.log.done_*`, since we no longer have a spinner stack.  "Fixes" #229.