Fix Date parsing inconsistencies in browsers

Added support in Model.set and setMany to instantiate an attribute value
using a constructor's `fromJSON` static method.

Support table: http://dygraphs.com/date-formats.html
Include only required files in NPM package
Test for passing options to nested models
Merge pull request #14 from avaly/fix/nested-options

Test for passing options to nested models
Merge pull request #13 from avaly/fix/only-required-files-in-npm

Include only required files in NPM package
Merge pull request #12 from avaly/fix/date-parsing

Fix Date parsing inconsistencies in browsers
Revert "Fix Date parsing inconsistencies in browsers"
Merge pull request #17 from Volicon/revert-12-fix/date-parsing

Revert "Fix Date parsing inconsistencies in browsers"