Display HTML tags in one string view

Fix issue #388
Merge pull request #389 from flodolo/issue388

Display HTML tags in onestring view
mozilla.org: don't display English for untranslated strings
Add view to display unchanged strings, reorganize JS code
Merge pull request #391 from flodolo/unchanged_strings

Add view to display unchanged strings, reorganize JS code
Update p12n-extract and productization view to use refactored JSON
API: return 400 and better message for missing entity

Fix issue #380
Merge pull request #393 from flodolo/productization

Update p12n-extract and productization view to use refactored JSON
Merge pull request #394 from flodolo/issue380

API: return 400 and better message for missing entity
Merge pull request #390 from flodolo/untranslated_mozorg

mozilla.org: don't display English for untranslated strings
p12n_extract.py - fix behavior for broken XML
Merge pull request #396 from flodolo/p12n_broken_xml

p12n_extract.py - fix behavior for broken XML