Modularization (JPMS)

[stechio]

Hi,

I really appreciate this project but, as already noted in other open issues (#116, #122), it needs to move to modularity in order to be on a level with modern java and, in the process, fix some related issues:

• com.vaadin.external.google:android-json dependency smells like a forgotten wreck (no update since 2014, no clear maintainer (does it even have a public repo?), no foreseeable support to modularity...) which should be replaced with an up-to-date alternative (e.g. openjson, cited here, looks promising)