Changes to IIPImage class contstructors to use more efficient member initializer lists, which are also necessary for compilation with clang compiler.
Plus minor cleanups to IIPResponse.cc and SPECTRA.cc
Changes to IIPImage, TPTImage and KakaduImage class contstructors to use more efficient member initializer lists, which are also necessary for compilation with clang compiler.
Updated hash map definitions to try to use unordered_map if available and fall back to hash_map or map. Now done more cleanly using autoconf detection.
Merge https://github.com/ruven/iipsrv
Merge with Ruven's master