Better shift readability

[Jar0T]

In ALU instead of doing huge case for shift operations you can do shifts like this:
s_result(15 downto 0) <= std_logic_vector(shift_left(unsigned(I_dataA), to_integer(unsigned(I_dataB(3 downto 0)))));
And same goes for right shifts.

Very cool project. I'm trying to follow it to design my own CPU.