* gmime-content-field.[ch]: Remove this. It was only a thin
	wrapper around struct _header_content_type anyway, and didn't
	match the naming scheme of anything else.

	* Makefile.am: Remove gmime-content-field.[ch]

	* camel.h: Remove gmime-content-field.h

	* camel-types.h: Add CamelContentType as a typedef for struct
	_header_content_type (especially for use outside of camel).

	* camel-multipart.c:
	* camel-mime-part.c:
	* camel-mime-message.c:
	* camel-folder-summary.c:
	* camel-folder-search.c:
	* camel-data-wrapper.[ch]: Use CamelContentType and
	header_content_type_* functions rather than the GMime stuff.

	* camel-mime-part-utils.c:
	* camel-medium.c: Remove unused gmime-content-field.h include.

svn path=/trunk/; revision=7186