capi.txt: add vhdl section

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
section: add verilog section

Remove verilog.py and handle verilog section like others.

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>
section: add vpi section

Remove vpi.py and handle vpi section like others.

Signed-off-by: Franck Jullien <franck.jullien@gmail.com>