Padding of the cwt_a function in pycwt.py fails when the signal length is odd.

[Takashi Sato]

You are trying to reduce the odd shift, but increased it.

The problem points are as follows　:
L.183 in pycwt.py
```
    padlen2 = evenp(siglen) and padlen1 or padlen1+1
```

It seems to be necessary to fix it as follows.
```
    padlen2 = evenp(siglen) and padlen1 or padlen1-1
```

[A Brazhe (brazhe)]

 Thank you, Takashi! I've now added the suggested fix