disable save button during image uploads

closes #1661

- disables save button at beginning of image upload
- enable save button at image upload fail, at image upload and download success and also at dropzone init
Fixes showing tag suggestions and tag container padding

fixes #1774
- Delayed showing the tag suggestions popup unless matching tags were found
- Changed the padding-left on the added tag container to 8px from 20px to fall in line with the left shadow overlay
Merge pull request #1814 from cobbspur/uploadsave

disable save button during image uploads
Merge pull request #1828 from ddoolin/fix-tag-suggestion-and-padding

Fixes showing tag suggestions and tag container padding
Disabled styles for disabled buttons

Duh
Adds ability to quickly get to post’s edit page

fixes #1810

- updates frontend.single route to accept ‘edit’
as the last param

- updates controller.frontend to handle redirection
only when we would otherwise have rendered the page

- added unit tests for this behavior
Merge pull request #1819 from hswolff/quick-edit-post-redirect

Adds ability to quickly get to post’s edit page