Reduce redundant memory copies in script construction

Add IEnumerable<> overloads to Script ctr and GenerateScriptSig
Reduce redundant memory copies in script construction

Add IEnumerable<> overloads to Script ctr and GenerateScriptSig
Merge branch 'script_enum' of https://github.com/dthorpe/NBitcoin into script_enum
Merge pull request #48 from dthorpe/script_enum

reduce script memory copies #2