Listen for 'close' event instead of 'exit' in for quiet

When firing the callback on the `exit` event, `out` and `err` are
empty. Changing the listened for event to `close` fixes this.
Fix linting warnings
Don't mix local/global options

Fixes case where calling `exec.quiet()` followed by
`exec.interactive()` would suppress the output from
`exec.interactive()`
Merge pull request #3 from alexwhitman/fix-options-overriding

Fixes options overriding
Merge pull request #2 from alexwhitman/quiet-output-fix

Listen for 'close' event instead of 'exit' in for quiet
0.2.3
Break up quiet, buffered and interactive exec modes. Fix serial output.

Uses streams for more efficent and faster buffered exec mode.
Merge branch 'master' of ssh://gh/zeekay/executive

Conflicts:
	index.js
Fix typo.
Ah yes semicolons.
0.2.4
Listen to exit event for buffered exec.
0.2.5
Expose different versions of exec, start writing tests.
0.2.6