Fixed the problem where when the user tried to install an unexistant
version, nodevers would raise an UnboundLocalError.
Nodevers now silences KeyboardInterrupts.
Changed the importing style.
Moved nodevers.install_helper.MissingToolError to nodevers.misc.
Renamed nodevers.misc to nodevers.shared.
Moved nodevers.cli.help_func() to nodevers.shared.
Moved nodevers.use.link_to(), .version.current_version,
.install_helper.NoSuchVersionError to nodevers.shared.
Bug fix.
Made error messages more consistent.
Moved some imports.
Just in case.
Added TODO file.
Bumped the version number.