Fix issue with _data folder parsing

Parsing timestreams with a _data folder was broken. To fix, we now:
 - exclude _* folders from extension guessing
 - exclude _* folders from image finding
 - fix IndexError bugs with bad timestreams
Also added a test case for this.
Remove unneeded test method.

* timestream/manipulate/pipeline.py (test): It used to test old code.
Initial commit of GUI to generate initial settings for image processing.
fixed an accidental error.
added timestream reading and color correction to GUI
allowed relative path to timestream root-path, added setting files, save previous GUI inputs
change settingPath to relative path in YAML file
suggest to include context pipeline __init__(), not process()
added test pipeline button
make settingPath relative to rootPath
try improving pot detection accuracy
made settings as class member