Move internal types to the end of the class file.
Remove reference to 'mapping' through closure.

We actually only need a reference to the "pwd" handler, not a
reference to the "mapping" variable.
Make all command definitions local.

The way eclipseaction works is pushing commands into a static variable,
thus creating commands for all tabs at the same time.

Make the CommandLineMode hold both the static coreCommands mapping and
a local mapping for user commands, then pass a combined mapping to the
CommandLineParser.

This alters the way CommandLineParser is constructed, so change all
tests as well.
Merge pull request #383 from albertdev/localcmdmapping

Make all command definitions local