Error during the SpiderProcessHandler

If Error during the SpiderProcessHandler, write a text file JOB_FAILED.txt to tell the uploader to upload the files without changing the status (that will be JOB_FAILED)
Upload even if JOB_FAILED

Adding code to check two flag files: the usual READY_TO_UPLOAD.txt and the new one JOB_FAILED.txt

If JOB_FAILED.txt, upload the files on XNAT (to see the outputs and outlogs) and leave the status to JOB_FAILED.
Update Process_upload.py

Adding the check for the flagfile
Update XnatUtils.py

Checking files/folders given to the SpiderHandlerProcess functions
Update XnatUtils.py
Merge pull request #15 from VUIIS/Job-failed-uploaded

Job failed uploaded
Merge branch 'master' of https://github.com/VUIIS/api.git into better_update
Merge changes from Job-failed-uploaded branch, fixed a few typos