Decoder class had a small problem

Suppose the following code:

```
d = Decoder(False, True)
```

It shouldn't fail. However I was getting the following:

```
Traceback (most recent call last):
  File "test.py", line 5, in <module>
    print(d.output())
  File "/home/petermlm/Documents/GSoC/BinPy/BinPy/Gates/gates.py", line 99, in output
    self.trigger()
  File "/home/petermlm/Documents/GSoC/BinPy/BinPy/Combinational/combinational.py", line 310, in trigger
    out[int(bstr, 2)] = 1
ValueError: invalid literal for int() with base 2: 'FalseTrue'
```

When I had a look at the trigger function of Decoder I noticed that I had to make the small change in this pull request.

Is this right? Should it work like this, taking booleans as inputs instead of integers?