Do not throw exceptions on storage events that are not json
Only emit change event, when the value has changed

This is especially relevant in IE, where events are not
only sent to other windows, but also the one, where the
action happens.
Do not waste time passing events for uninteresting events

That e.g. are emitted in InternetExplorer.
Compile to javascript
Bump into 1.1.1
Merge pull request #4 from anderslime/robustness-level-added

More expected behaviour for memojs event emitting in IE