Add translations tests

Add a new test suite to verify the correct usage of the t() functions.

For instance:
t2('%s test', '%d tests', 1);
is wrong, since gettext can't compile the .po file (for the above example
msgfmt exits with the error message
"format specifications in 'msgid_plural' and 'msgstr[0]' for argument 1
are not the same")
the one, the only, the clear cache page #282
SEO excluded URL Word List #279
header and footer stuff
Merge pull request #328 from evancooper/clear_cache_page

the one, the only, the clear cache page #282
Merge pull request #329 from evancooper/excluded_url_word_list

SEO excluded URL Word List #279
updated file paths in help text
Merge branch 'master' of github.com:concrete5/concrete5-5.7.0
Merge branch 'master' of github.com:concrete5/concrete5-5.7.0
Dashboard responsivity and panel goodness
fixing search page
making topics work again
Add `preview as user` to the editmode panel in advanced permissions mode
Resolves #11
Add date to default, fix permission duration settings
Fix race condition in preview detail panel
just crushing it, really
fixing next previous nav edit interface, wrapping radios in labels and making hr not duplicate when switching between modes
fixing issue with buttons in fieldsets getting disabled #330
UI changes for 5.7
Add scrolling to edit mode block drag
This fixes #36