Start migrating to Add-on SDK

Re-organize project directory structure.
Port jsonview modules
The sdk does not allow UTF-8 BOM
Port addon preferences
Addon icon32 and 64
Add build script

Since the Addon SDK requires python, the build script should be written
in this language
Update Readme to use Add-on SDK for development
Merge pull request #52 from vietnq/addon-sdk

Migrate to Add-on SDK