Update LocalStorageHandler.js

Switch to serialize ALL values instead of "object" type only.

var lsh = LocalStorageHandler
assert(lsh.set('foo', "'bar'") == lsh.get('foo')) // fails because lsh.get('foo') evaluates to "bar" instead of "'bar'"
assert(lsh.set('foo', "null") == lsh.get('foo')) // fails because lsh.get('foo') evaluates to null instead of "null" (a string)

Thanks to @marcuswestin for the tip.