Add VideoBam as requested in #117

Edited as requested in pull request #385 .

Works fine with my machine: OSX 10.4 Python 3.3.2

```
Beining$ python3 you-get http://videobam.com/tourVideo Site: VideoBam
Title:      A Quick Tour of VideoBam
Type:       MPEG-4 video (video/mp4)
Size:       6.27 MiB (6574552 Bytes)

Downloading A Quick Tour of VideoBam.mp4 ...
100.0% (  6.3/6.3  MB) [========================================] 1/1 
```