Feature emit appcall

[localhuman]

What current issue(s) does this address?, or what feature is it adding?

• Adds the ability to chain contract invocations by building them with ScriptBuilder
• Works for invocations with or without an array of parameters
• Replaces existing tested functionality, no additional tests added

** Sample Usage **

        sb = ScriptBuilder()
        sb.EmitAppCallWithOperation(self.ScriptHash, 'name')
        sb.EmitAppCallWithOperation(self.ScriptHash, 'symbol')
        sb.EmitAppCallWithOperation(self.ScriptHash, 'decimals')

        tx, fee, results, num_ops = test_invoke(sb.ToArray(), wallet, [])

[localhuman]

This resolves #100

[coveralls]

Coverage increased (+0.05%) to 68.375% when pulling 851b946 on feature-emit-appcall into 0c0b7be on development.

[metachris]

Great!