Fix and improve status/refresh-test

Add a missing assertion for the command mentioned in issue #289 and
extend the test to test both checkout of modified and deleted files.
Change test scripts to always wait for previous command to finish

Simplify the script execution by eliminating the `:wait` command. The
asynchronous behavior only renders the tests non-deterministic.
Add refs/default-test
draw_text_overflow: fix wrong offsets for multibyte text.

[ jf: change to use utf8_length; added test ]