Merge pull request #21 from KorolevSoftware/master

Adds sys.serialize from fix json serialize dangers

Merge pull request #19 from KorolevSoftware/fix-json-error

Fix json error

Merge pull request #18 from e1e5en-gd/master

Fix issues #17

Merge pull request #15 from Vbif/master

ensure boolean would be in lowercase when serializing

Merge pull request #13 from subsoap/html5-try-catch-localstorage

Fix crash related to localStorage on iframe + incognito Chrome

Merge pull request #11 from endel/html5-localstorage

use localStorage for HTML5 builds

get() should return nil instead of an empty table

Facilitates patterns like

```
self.time_passed = defsave.get("state", "time_passed") or 0
```

get() should return nil instead of an empty table

Facilitates patterns like

```
self.time_passed = defsave.get("state", "time_passed") or 0
```

fix

Use deepcopy for get/set