parse command line arguments.

This changes the main documentation, doc strings, source code comments, and a
couple error messages in the test suite. In some cases the word was removed
or edited some other way to fix the grammar.

Patch by TAKASE Arihiro.

robust at shutdown. If needs to release multiple resources, they are released
even if errors are occured.

Patch by Marc Abramowitz.

Patch by Karan Goel.

This allows use with special filesystems such as VirtualBox shared folders.

Patch by Francis MB.

Pointed out by Arfrever.

Patch by Ian Cordasco, approved by Éric Araujo.