Fixed file output bug

Fixed a bug that set the output filename to the data read from the
HRM.
Added an example of a udev rule file

Added an udev rule example file, to permit access to Megawin MA101
USB bridge devices.
Added interpretation of data

To add interpretation of the data read from the HRM there two classes
were added Parser and HRMReport. Only 4 variables are recognized now:

 - Gender
 - Height
 - Maximun heart rate limit
 - Minimun heart rate limit

As every class needs to raise exceptions, the HRMException class was
also independized.

There were several typos corrected