Option to consider bare multisig scripts in TX outputs non-standard

First and foremost, this defaults to OFF.  Perhaps consider changing the default if the community feels strongly about the issue and/or a security issue strongly encourages a change.

This option lets a node consider such transactions non-standard.

This impacts parties using CheckMultiSig for multisig and parties using CheckMultiSig for raw data transport.

This also makes a sigops-related issue harder to express in practice.

WARNING:  An issue @gavinandresen raised has not yet been tested.  Do not pull at this time.