[WIP] Implement server-side conversation upload files feature
Merge remote-tracking branch 'origin/master' into upload
[WIP] Add sign for uploaded files
[WIP] Implement uploading files to the conversations. See #112
Merge remote-tracking branch 'origin/master' into upload

Conflicts:
	public/js/pjax/pjax-navigation.js
[WIP] Add loading.gif for file uploads. Add new line for images
[WIP] Replace attachments in conversation list page
Fix mime check. Closes #112
Revert "Fix message sending. Closes #116"

This reverts commit d2d8ed86b20f49127bf37a1316509d862239cc20.

Conflicts:
	public/js/site.js
Fix ajax send message attachment handle. Extract attach handle function. Closes #112
Merge pull request #149 from boo1ean/upload

Media in messages feature