Implemented part of ticket #477
- Renamed cache.cpp and cache.hpp with memorymanager.cpp and memorymanager.hpp
- Changed default table name to "table()"
- Cleaned the implementations of "med()" and "pct()" functions
Implemented part of ticket #477
- Removed all references to DataFile
- Relaced the references with MemoryManager
- Extracted the (deprecated) pasting functionality into the PasteHandler class