Adding features showing ETA, final time, and optional meter

Adding a roughly calculated ETA and final time to 100%.
Optionally, the user may specify a meter M characters
long, made of hash signs and spaces '#########        '
Added an additional test, and modified description
Cosmetic bug fix - insure the percentage occupies a fixed position

The whole meter was shifting when progress went from single digits to
double to triple (100%).  Now the string remains "fixed".
Refactor - renamed methods, added comments
Adding acknowledgement to python-progressbar for visual design
Merge pull request #2 from abahm/master

Adding features showing ETA, final time, and optional meter