ND2: fix tile reading when the X coordinate is > 0

Fixes #12454.
travis: Switch from raring to saucy

raring has been removed from the mirrors and was no longer supported
Merge pull request #1219 from rleigh-dundee/travis-saucy-dev50

travis: Switch from raring to saucy
Merge pull request #1215 from melissalinkert/rebased/dev_5_0/12454

ND2: fix tile reading when the X coordinate is > 0 (rebased onto dev_5_0)
Merge remote-tracking branch 'origin/dev_5_0' into rebased/dev_5_0/fake-reader