Make some tx_pool methods private
Make some tx_pool methods const
Remove get_transaction
Make get_transactions void
Make some tx_pool methods static
Make transactions lock mutable

I assume this makes the new const methods play nicely.
Update print_pool and make it const correct
Add transaction size limit
Clean up on fail to load tx_pool from file
Add minimum tx fee
Ignore deserialize error
Use print_money in log
Change max_total_size in fill_block_template
Change transaction upper size limit in wallet