This reverts commit ed80381b, reversing
changes made to 205cb8b3.

FEDX-121

The previous approach for handling NPM assets was
to symlink them into the static directory. This appeared
to cause trouble with the asset pipeline where the files
in question were not installed and then old versions were
picked up instead.

This change instead copies NPM libraries to a new
static directory so that the pipeline can consume them
as with any other file. This new directory is added to
.gitignore so that the files don't get accidentally
checked in.

* Fix paver violations to stablize edx-lint update
* Parens, Line2Long
* Fix missing docstrings
* Fix PEP8 issues
* Address PR feedback (thanks @nedbat!)

TNL-2465

This allows developers to pass the `--pdb` flag to paver test commands,
and that flag will be proxied to the `nosetests` command. It's useful
for debugging purposes.