Add <br/>s in the Welsh title on the homepage

Otherwise the long title overlaps the flying computer logo.
Use escape_javascript on translated strings in Javascript strings

The Welsh translations of some of these words contain single quotes;
escape them in the view so that the Javascript doesn't contain
syntax errors.
Latest version of Welsh translation

Includes interpolated variable name fix for "Efallai y byddwch yn gallu
dod o hyd i un ar eu gwefan, neu drwy eu ffonio nhw a gofyn. Os
llwyddwch i ddod o hyd i un, <a href=\"{{url}}\"> anfonwch e atom</a>."
Merge branch 'welsh-fixes' into wdtk

Conflicts:
    locale/cy/app.po