Beta version ready!

The beta version has been tested on a Gullwing development board from Gennum.
For testing purpose, one 8KB RAM is connected as a slave on the DMA wishbone.
Two slaves are connected to the CSR wishbone. One contains four status registers, three with fixed values and one with the state of the on-board DEBUG switches. The other slave have four control registers and one of them is controlling the on-board LEDs.