* spam.el (spam-use-stat): new variable

* spam.el (spam-use-stat): new variable
(spam-group-spam-processor-stat-p)
(spam-group-ham-processor-stat-p): new convenience functions
(spam-summary-prepare-exit): add spam/ham processors to sequence
(spam-list-of-checks): add spam-use-stat to list of checks
(spam-split): conditionally load the spam-stat tables
(spam-stat-register-spam-routine, spam-stat-register-ham-routine,
spam-check-ifile): new functions

* spam-stat.el (spam-stat): typo fix
(spam-stat-install-hooks): new variable
(spam-stat-split-fancy-spam-group): added documentation clarification
(spam-stat-split-fancy-spam-threshhold): new variable
(spam-stat-install-hooks): make hooks conditional
(spam-stat-split-fancy): use spam-stat-split-fancy-spam-threshhold

* gnus.el (gnus-group-ham-exit-processor-stat, spam-process): add
spam-stat ham/spam processor symbols