Adds an option -P to print content types
Adds an option -P to print content types

* Don't ask the user to rummage through the package.
  Just let them use this option to show them all the content
  types known to pepe at runtime.

Signed-off-by: Yesudeep Mangalapilly <a2078c57e3ac12c6dfb97b7c2c4e6d6d7db7e92f@gmail.com>

gorakhargosh/pepe