added an indexed vector type creating a PartialMap[V,Double] view from a Vector and an Index[V]
added an indexed vector type creating a PartialMap[V,Double] view from a Vector and an Index[V]

cilier/breeze,ktakagaki/breeze,mredaelli/breeze,nikdon/breeze,wstcpyt/breeze,scalanlp/breeze,crealytics/breeze,claydonkey/breeze,ktakagaki/breeze,ContentSquare/breeze,sheide/breeze,calippo/breeze,tjhunter/scalanlp-core,eponvert/breeze,chen0031/breeze,tjhunter/scalanlp-core