Processor first draft

All necessary components are initiated but the connections are not
complete yet.
2nd draft

code not synthesizable; shift left missing -> take signed numbers in
account
Control Unit improved

No there are no latches anymore when synthesizing the control unit.
Still, the values of the control signals have to be checked again for
each state.
Unimportant additional ise files
processor finished but not tested yet

Calculation and Updating of PC implemented. Reset implemented.
Description of Control_unit modified so that there are no latches
anymore.
Control unit testbench finished

Control unit works fine. No Signal delays between a change in the output
and in the control signals anymore.
Unimportante ise files
Unimportant ise files changed
processor merged in master branch

control unit not merged yet