Plan status view

- bundle install
- rake db:migrate
Creates a view summarising the status of a plan (when sections were
locked and by whom, when questions were answered and by whom). Uses the
Schema Plusgem to generate the views (two supporting views needed) via
migrations. The idea is to improve the performance of the plan editing
page by reducing server load.
Also includes the Better Errors gem.
Streamlining

Trying to reduce system resources needed to view plan status
Better checking for unsaved answers

Use of isDirty() to check if TinyMCE text areas have been updated
without being saved is more reliable.
Checking for unsaved answers no longer requires an AJAX call.
Alert on closing section shows which answers are unsaved.
New alert on navigating away includes details of unsaved answers (could
be ordered better).
Needs further testing with other (non-textarea) question types.
Rolled back plan summary database view - was having a detrimental
effect on performance. Removed corresponding gem.
Visual tweaks

Avoiding long list of questions in unload alert; making “unsaved
answers” label more visible. Also fix for read-only access bug.
Add pdf export space indicator.

This takes a rough guess at how much space is going to be used in the
exported pdf, based on the estimated number of lines, font-size and margins.
Merge branch 'export/format-settings' into export/space-used
Round space used estimate up to nearest 5%
More descriptive progress titles
Update export space progress on JS save
More space between progress bars and form
Merge remote-tracking branch 'upstream/master' into export/space-used
Allow multiple settings forms for multiple plans
Re-use href var
Estimate characters in line based on font size
Add and use max_pages template setting for space used progress bar
Allow setting dmptemplate max pages settings in admin
Correct labels in dmptemplate settings form
Turn space used progress bar red when full
Don't include blank answers in status['num_answers']
Add to num_answers if the question is multiple choice.