Fix for missing 'discard draft' icon in front end editor

Problem caused by upgrade to latest font awesome library

[skip ci]
Tidying up messages and styling of loading and erroring images in the ckeditor image insertion plugin

[skip ci]
Making the 'spinner' control just use the new HTML5 number input

Way better than the broken spinner js form control we were using

[skip ci]
Enhancing the image insertion form for richeditor with extra fields

Now has spacing, caption, copyright and link fields + presented in lovely tabs

[skip ci]