Remove extra period from Spanish translation

I was browsing around Diffux in Spanish and I noticed double
punctuation. This commit fixes that problem.

Change-Id: I4d1d70db552e71262619b8a4639c9029ab412aa4
Actually update diffux-core gem

When I bumped the gem version, I failed to commit the Gemfile.lock
changes.

Change-Id: Ib489cebabc78ce2d9fa68832b67821fcfa9256f6
Fix another double-punctuation in Spanish translation

The punctuation for this string is in the view, so we don't want it here
in the locale file.

Change-Id: I43aba0d80056a306b22d70903675095342555957
Remove punctuation from model attribute in Spanish translation

These attributes are used for form labels and should not end in periods.

Change-Id: Iaaaf9c165d702357d746020078dfaa1556ada3e2