Fix many links, implement better link system

 - Fixed links for "Argparse" and "easy_install" in directions sections.
 - Implemented index based link system (less confusing to write).
 - Fixed a few problems which was arising by previous linking system.
Merge pull request #47 from santosh/master

Use more consistent markdown hyperlinking for the README file.

The old way could, potentially, bit us in the future. The new way may be more
cumbersome, but it is safer.
First try to use BeautifulSoup 4, then try BeautifulSoup 3.

BeautifulSoup 4 is potentially faster (and, if the placebo effect isn't
operating here, it does work faster on my 400MHz ARM-based NAS with 128MB of
memory).

To get the most benefit from BeautifulSoup 4, the user should install
python-lxml, which consists of Pythonic bindings to the libxml2 and libxslt
libraries (written in C).
Revert "First try to use BeautifulSoup 4, then try BeautifulSoup 3."

Although I can't reproduce it, some people seem to have found problems with
the use of BeautifulSoup 4 by default. This hopefully fixes issue #48.

This reverts commit f79dddeece30d696d9ec2ea6f6fb5c05eea9c397.
Add instructions for reporting bugs that are useful.
Rewrap long lines in the readme file.
Fix (sub-)bullets that were broken by a previous commit.
Reword the documentation slightly.
removed reference to cookies
Added -k option to curl command
Fixes curl failing trying to verify coursera certificate
Added netrc path as user option
Use --netrc with path. If no path is given or --n, -c and -u are omitted
a default netrc path is tried ($HOME/.netrc on *nix* or
%USERPROFILE%\_netrc on windows).
Print bandwidth in addition to the number of downloaded bytes.
Changed logging level for several log messages
- changed logging of resource urls from info to debug
- added 'downloading' and 'already downloaded' info messages
Changed logging formats to some more readable format

- Debug format: levelname[funcname]: message
- Error format: levelname: message
- Info format: message
Curl output now as progress bar incl. percentage done
added longer class name to readme examples
Merge pull request #56 from thomasballinger/readme-long-coursename-example

add longer class name to readme examples
Merge pull request #53 from sdbakker/master

* Unify the handling of netrc files.
* Adjust the log level of some messages.
* Prettify curl's output.
Merge pull request #55 from igors/bandwidth

Print bandwidth in addition to the number of downloaded bytes.
test: Add example of a preview page.