Added support for a total message count on accounts and folders.
4.506 changelog
Bumped manifest to 4.506
Merge branch 'master' of git://github.com/k9mail/k-9 into foldercounts

Conflicts:
	src/com/fsck/k9/controller/MessagingController.java
	src/com/fsck/k9/mail/store/LocalStore.java
Implementation of folder/account message counts.
Fixed spelling.