More progress bar aesthetic changes

This commit introduces two new changes to how the progress bar looks:
1. Support the --progress=bar:noscroll option which will prevent the filename
   from scrolling in the progress bar
2. Print human readable value for the amount already downloaded for any file
Whitespace and formatting changes.(Aesthetic only)

This commit makes lots of whitespace only changes. It has been ensured that this
commit does not make any changes to the functioning of the program. The only
changes that have been made are:
    * Remove trailing whitespaces
    * Convert tabs to spaces
    * Fix indentation issues in the code
    * Other aesthetic changes to the formatting of comments