Add option to display internal module names on Modules List page

This patch adds the option to display Internal Names of modules on the Modules List page. The internal name is what Drupal knows the module as -- it's what all of the source files are pre-pended with, what all of its implemented hooks begin with, the name of the directory it's located in (and the name of the tarball file when it's downloaded), etc. This solves the problem that every Drupal user runs into sooner or later of knowing what a module's internal name is (because they just downloaded it), but then being unable to locate it on the Modules List page because it goes by a different name.