Allow the user to place an order in eth2btc.sol by making a deposit

[bitcoinwarrior1]

• User can place an order by locking up a small deposit of eth for a set interval of time (enough time for them to make the btc transaction and receive confirmation). This locks a portion of the eth in the contract just for them.
• When making a deposit, the user set's their btc details including their address
• User receives an order id
• After user sends btc, they can claim the eth and get a refund for the deposit
• If the user does not send the btc and the time lapses, the deposit is given to the MM and the eth becomes available again