This is a cleaner approach that requires less configuration
in other applications.
This also easily allows us to have another color.
Many checks were made on being exactly at the DEBUG level, they were
fixed to also check on being below DEBUG (i.e. DEBUG_FILTERS).
- error callback for loadHistory, to make the reload button enabled again after an error
- remove descriptionEdit's placeholder (for compatibilty with earlier versions of Qt)
- add placeholder text to descriptionEdit if supported by the user's version of Qt
- set contentEdit read-only while loading a new page
- saveButton was still showing "Saving" after saving had failed
- The 'save' button is disabled and shows 'No changes' at first. Editing contentEdit's text
enables the button and makes it show 'Save'.
- The 'save' button is disabled and shows 'Saving...' when the page is being saved, and stays
disabled until contentEdit's text has been changed again.
- The 'save' button shows 'Saved' once the page has been successfully saved. fixes#560
- contentEdit is readonly when the page is being saved
The preview text displayed in the previewEdit widget was the text of
the content opened from the wiki, and not the text entered by the user
in the contentEdit widget.
- content preview's html code is now cleaner
- ICapContent.preview_content() renamed to ICapContent.get_content_preview()
- tab "preview" was shown first when starting qwebcontentedit. Fixed.
