parametrize memory size
the memory size (together with the chosen DRAM chip) determines the number of ranks
memory port request tags, minor refactoring
memory ports now mark which kind of req they are generating (useful for statistics generation - e.g monitoring the composition of the bandwidth)
removed unused memory request/response generation functions
support for more memsys config and info querying
report peak bandwidth, change defaults
assume a 4GB 12.8 GB/s DDR3-DIMM (PC3-12800)