add comment to HelpMessage() to ensure alphabetical ordering
add comment to HelpMessage() to ensure alphabetical ordering

- also rename hmm to mode, to be consistent between .h and .cpp

(cherry picked from commit 1020f599f33d47812a5ed73366fd266a25fef32d)

# Conflicts:
#	src/init.cpp

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin