[Feature] No error reported for invalid delay constant

[AlexandreSinger]

The following XML should have produced an error, but it did not:

<mux name="mux1" input="arithmetic.in_C ff.Q" output="lut4_wrapper.in_C">
  <delay_constant max="1.1347e-10" in_port="flut5.in_C" out_port="lut5.in[2:2]"/>
  <delay_constant max="1.1347e-10" in_port="ff.Q" out_port="lut5.in[2:2]"/>  
</mux>

The delay constants are going to and from the wrong ports. We should throw an error in this case.

[AlexandreSinger]

There is also no error reported when we have duplicate interconnect names:

<interconnect>
  <direct name="direct1" input="fle.in_A" output="ble6.in_A"/>
  <direct name="direct2" input="fle.in_B" output="ble6.in_B"/>
  <direct name="direct3" input="fle.in_C" output="ble6.in_C"/>
  <direct name="direct4" input="fle.in_D" output="ble6.in_D"/>
  <direct name="direct5" input="fle.in_E" output="ble6.in_E"/>
  <direct name="direct6" input="fle.in_F" output="ble6.in_F"/>
  <direct name="direct7" input="ble6.out_local[0:0]" output="fle.out_local[0:0]"/>
  <direct name="direct7" input="ble6.out_local[1:1]" output="fle.out_local[1:1]"/>
  <direct name="direct8" input="ble6.out_routing" output="fle.out_routing"/>
  <direct name="direct9" input="fle.clk" output="ble6.clk"/>
</interconnect>