Update "labelme.py"

  - checking ROI, then warning
Update "easy.py"

  - update message when BOI error
Update BoW algorithm-related codes

1) message to clients
2) ROI-related message
Update BoW algorithm-related codes

1) message to clients
2) ROI-related message
Update BoW algorithm-related codes using MsgLogger class

1) message to clients
2) ROI-related message
Merge pull request #102 from lekomin/feature-occluded

Update BoW algorithm-related codes using MsgLogger class