Symbolic names for submission_status

[bemoody]

The submission_status field of ActiveProject uses integer codes to indicate the status of a project. These values are hard to read and hard to search for. Symbolic constants should be easier to read and maintain.

There should not be any functional changes here. Verifying I didn't change anything accidentally in the last commit:

for f in $(git diff --name-only HEAD HEAD^) ; do diff --label $f -u <(git show HEAD^:$f) <(git show HEAD:$f | sed 's/SubmissionStatus.UNSUBMITTED/0/;s/SubmissionStatus.NEEDS_ASSIGNMENT/10/;s/SubmissionStatus.NEEDS_DECISION/20/;s/SubmissionStatus.NEEDS_RESUBMISSION/30/;s/SubmissionStatus.NEEDS_COPYEDIT/40/;s/SubmissionStatus.NEEDS_APPROVAL/50/;s/SubmissionStatus.NEEDS_PUBLICATION/60/'); done

[bemoody]

I'll fix the formatting later, BTW. Anyone should feel free to propose better names for these constants. :)

[tompollard]

Definitely an improvement, thanks. Once the style checks are passing, this looks good to merge.

[tompollard]

@bemoody I took the liberty of fixing the style issues! Let me know if you'd prefer I didn't do this in future.