(ReadIndexV2): use Binary.GetCString instead of ArcView.ReadString.
(ReadIndexV2): use Binary.GetCString instead of ArcView.ReadString.

temporary buffer allocation within ArcView.ReadString makes reading of
large indices (20000+ entries) somewhat slow.

dsp2003/GARbro,morkt/GARbro,dsp2003/GARbro,dsp2003/GARbro,morkt/GARbro