Remove all ur's

PEP 414 re-introduced the u'...' syntax, but not the ur'...' syntax. This
means we have to re-write all non-ASCII regexps in some way.

I used different methods, depending on the context.
 1) ASCII regexps, or regexp that get the unicode parts formatted (%s) in:
    --> replace ur'...' by r'...'
 2) Regexps that do not contain any backslashes
    --> replace ur'...' by u'...'
 2) Regexps with a single unicode part, e.g. ur'\{\{ä\}\}'
    --> replace by r'\{\{' + u'ä' + r'\}\}'
 4) Complicated regexps
    --> copy-paste into python 2, and copy-paste the repr() back

Change-Id: Ifd17b508baafcb30016d314852472371e47fa79c
Merge "Remove all ur's"