Show parse error message during a failed import

adds support for outputting error message during a failed JSON.parse
This will help people identify the problem with their JSON source
and hopefully be able to aid them in resolving said issue.
abstract mobile interactions js

DRY up repeated code and simplify logic.
Merge pull request #2071 from samccone/sjs/show-error-on-import-failure

Show parse error message during a failed import
Merge pull request #2221 from samccone/sjs/clean-up-mobile-actions

abstract mobile interactions js
Remove useless regex for redirecting /ghost -> /ghost/
Fix Firefox <select> height issue

closes #1109
- Use moz-specific selector to make <select> elements use auto height
Respect subdirectory in authenticate middleware
Merge pull request #2223 from mjbshaw/fix-subdir

Respect subdirectory in authenticate middleware
Merge pull request #2224 from mjbshaw/useless-regex

Remove useless regex for redirecting /ghost -> /ghost/
Merge pull request #2228 from PaulAdamDavis/master

Fix Firefox <select> height issue
Updated pageUrl helper to page_url

issue #2216
Merge pull request #2222 from knunery/issue#2216

Updated pageUrl helper to page_url