Additions to simution support.

Adds verilator support: systemC and C++ descritions.
Convert verilog define files (.v) into C define files (.h).
Adds icarus specific dependencies.

	modified:   orpsoc/core.py
	modified:   orpsoc/simulator/icarus.py
	modified:   orpsoc/simulator/modelsim.py
	modified:   orpsoc/simulator/simulator.py
	modified:   orpsoc/simulator/verilator.py
	modified:   orpsoc/utils.py
Merge branch 'vlt2pull' of https://github.com/Carlosaarodrigues/orpsoc into vlt2pull

Conflicts:
	orpsoc/simulator/icarus.py
	orpsoc/simulator/verilator.py
	orpsoc/utils.py