General Impovement: correction, comments

- Correct the implementation of Constraint Demotion
Mainly caused by incaution with positive degrees when subtract() and
discard() explainable candidates
- work rightly for "Ilokano.txt"
- resolve the errors when running "Hebrew.txt"
- improve comments
- improve codes
- rearrange
- InputError for tableau module
- check input for harmonically bounded surface(winner) form
- GUI: message box for ERROR infomation