The new formatter was ignoring selected headers, always displaying
only From, To, Subject and Date (default headers).
Handling of the currently displayed headers has been moved to
EMailConfigFormatHTML extension, because it is related to
configuration of EMailFormatter, rather then EMailReader.
All mail-parsing and formatting code has been moved to em-format.
Parsing is handeled by EMailParser class, formatting by EMailFormatter.
Both classes have registry which hold extensions - simple classes
that do actual parsing and formatting. Each supported mime-type
has it's own parser and formatter extension class.
The EModule, EExtensible and EExtension classes as well as the
e_type_traverse() function have been moved to Evolution-Data-Server's
libebackend library to replace e-data-server-module.c.
Now Evolution-Data-Server modules use the same framework as Evolution.
