uncrustify.cfg: label indent, some known types, not, # and ##

Adjusted some uncrustify variables to get closer to prevailing style:

* Label indent (for goto) relative to current indentation.
* Registered GMimeObject and mime_node_t being as types.
* Space after ! (not) operator.
* No space after 'stringify' (#) preprosessor token.
* No spacing change around ## (option not versatile enough).

There are at least 3 cases where attention needs to be paid:

* If there is newline between function name and open paren in function
  call, the paren (and args) are indented too far right.
* #define HOUR (60 *MINUTE) -- i.e. no space after star (*).
* void (*foo)(args) -- i.e no space between (name) and (args).