QFJ-795: "MsgSeqNum too high" should not be an error
 - changed Session to treat too high seqnums as a normal condition since situation will be handled automatically by FIX protocol
fix whitespace formatting
fix javadoc formatting
add missing license headers
modified README for sandbox repo
use FIX 5.0 SP2 by default
use FIX 5.0 SP2 field value constants