Added Synthesis (resources analysis) , improvement of LRU (uses less resources and easier to read) and development of a new LRU replacement policy (LRU_stack, still in testing)

[joaovroque]

• Added hardware/fpga/ in order to synthetize the cache (or other module, just change the top's name in synth.tcl): an easier way to analyze the resources, specially for remote work (opening the GUI is an impossibility (time-wise)).
• Added another approach to the LRU algorithm (`LRU_stack), which uses shifts instead of counters, simulating a Stack like priority (where the MRU is the Heap and LRU is the Tail). Unfortunately the performance is either the same or worse, the simulation of the iob-cache with it fails, despise working in the rp simulation and in dryhstone testbench. - Do not use this, currently.
• Improved LRU algorithm (`LRU). Uses 3% (at 16 Ways) less resources, while being easier to read (and therefore to represent and explain). Has the exact same results in the Dryhstone test (it's doing the same).