call RSET POP3 command to reset "seen" flag if supported by the POP3 server
darcs-hash:20060726194755-86b55-3e17c219f71aa5ca4db65f6ad8131c0222dd85b0.gz
- reorganize classes
- make it run even when pysqlite2 is not installed
- some tests to complete mailconnection_factory coverage
darcs-hash:20060724214007-86b55-9b38308b8f645c2067c7b200f17532da62ec825c.gz