EComposerActions: When composer is not editable make more actions insensitive
EWebView: Don't need to check for WebKit version
EComposerPrivate: Quote composer content just in HTML mode
Add support for inline (CID) images

With this change all the inline images inserted into composer
(emoticons as well) are upon their insertion encoded to base64 and the
outcome is set to src attribute of the HTML image element. When sending
the message for all these images the CamelMimeParts are created and
attached to it. When saving message as draft no changes are made.  When
opening the message as new (and the message containes CID images) the
content from all the CamelMimeParts with images is encoded again to base64 and
saved. When the message is loaded the CID sources are replaced with
base64 data.The core functionality was moved from EMsgComposer to EEditorWidget
because right now it is too tight with DOM of the composer's web view.
EEditorWidget: Replace images http(s) source to evo-http(s)

This prevents the Web View to download image straightly but it has to go
through EHttpRequest
EEditorWidget: Refactor the function to process the composer's content

Also fix some minor bugs i.e.  hiding the caret position when saving
message as draft. Also the GRegexes used there were created and afterwards leaked
on every level of DOM tree.
Add support for Drag&Drop of base64 encoded images

These images can be found in the attachments below the received message.
Add support for Drag&Drop of CID images from message preview into composer