* Added simple genesis block timestamp setting to help testing
* Fixed setting account's last reference
* Moved some Poll constants from CreatePollTransaction to Poll
* HSQLDB: added TYPE PollOptionIndex
* HSQLDB: added previous_option_index to VoteOnPollTransactions table to help orphaning
* HSQLDB: renamed "poll" to "poll_name" in same table
* HSQLDB: PollOptions now has additional option_index column
* Improved TransactionTests to allow for different genesis block timestamps.
* Also added VoteOnPollTransaction test