1. configs are not functional
* decorator will be executed when search case, need to set default config before search case.
2. fix DUT encode/decode errors
* python3 serial don't support write string/unicode, need to convert to bytes first.
* python2 string could failed to encode/decode non-acsii chars
3. fix bug that log folder not created
4. fix bug that test suite name is not correctly passed:
* the keyward arg should be `test_suite_name` not `test_name`
5. fix bug that test stopped on failed case
6. fix DUT `read` don't return all data cache
* `_DataCache.get_data` should first copy all data from queue to data cache and then return to user.
7. fix bug that `expect_all` failed even all expected item passed
8. optimize error info for expect
* print pattern for regular expression when match failed
9. fix bug that set default config doesn't work
1. Attenuator: control programmable attenuator
2. PowerControl: control APC PDU to power on/off devices
3. LineChart: use matplotlib to draw line chart
