helper extensions for ITransactionRepository to handle string txids
Merge branch 'txrepo_extension_methods' into txrepo_extensions
Merge pull request #36 from dthorpe/txrepo_extensions

Txrepo extensions
Merge pull request #40 from dthorpe/master2

Add ID convenience property to BitcoinSecret
Using interface instead of class if ColoredCoin.Find, 1.0.6.3