possible issue in protocol - two order matches not possible for btc tx

[radiumsoup]

may need to send this to the counterparty reference client github - it appears a partial match on a btc/x transaction will cancel the remainder of the sell order - BUT, counterwallet still shows the partial order as open instead of cancelled or expired.

steps to recreate:

1. place a sell order for quantity 2 of a counterparty asset at a price divisible by 2 without rounding
2. using another address, place an order selling btc for quantity of 1 of that same counterparty asset, but only for half (ensure the price is still such that an order match will occur)
3. the order will show as matched using xchain, counterwallet, and btc2xcp
4. make the bitpay transaction through btc2xcp
5. verify order is complete
6. verify order from step 1 is still listed as open on xchain and counterwallet
7. observe order from step 1 is listed as "expired" on btc2xcp
8. place a second buy transaction identical to step 2
9. order from step 8 will not match in xchain, counterwallet, or btc2xcp