Add Readline keydown listener test.
Add Readline.submit test.
Add Readline.newer/older history tests.

These tests are only for an active command history.
Add Readline.newer/older empty history tests.
Add Readline.keydown down keystroke tests.
Add Readline.keydown up tests.
Make the describe lines more accurate for arrows.
Add Readline.keydown enter tests.
Merge pull request #100 from mcomella/test_readline

Add Readline tests