Add option to avoid spending unconfirmed change
Move IsPushOnly() to script.cpp
Add HasCanonicalPushes(), and use it in IsStandardTx
Merge pull request #3025 from sipa/noncanpush

Make signatures with non-canonical data pushes non-standard.
Merge pull request #3651

1bbca24 Add option to avoid spending unconfirmed change (Wladimir J. van der Laan)