re-engineering notes

LruCache<> uses custom allocator and custom linked list --> make it STL with pool allocator
SmallHash<> has custom allocator --> use C++ STL conform allocator


cache module --> cache manager
download: proper abstraction of "network path"
central statistcs service
enforce code style dicipline
namespaces: use anonymous namespaces more systematically, review use of namespace together with moving source files into subdirectories (name spaces reflect relative path)
REWRITE the hash abstraction! (templates, no manual alloca for ContextPtr)  <--  OBSOLETE due to special requirements for hashes
Replace cvmfschecksum.$fqrn special format by manifest
history databases become dangling at each update (no pointer to previous history)
remove micro catalog legacy from the code base