RFR: Further support for JSON-based module-info descriptors

[David Bosschaert]

Hi all,

I've expanded the JSON-based module descriptor support. I think it now
supports all the features that module-info.java supports.
I also added encoding detection to the JSON parser code. According to
http://www.ietf.org/rfc/rfc4627.txt section 3 a JSON file should
always be in unicode. The JSON parser can now deal with UTF-8, UTF-16
and UTF-32 (there are test files included to test this functionality
too).
Also added, more tests, including a test that shows how a
module-info.json file can be expanded with custom metadata, very much
like what it could look for OSGi.

You can find the webrev here:
http://cr.openjdk.java.net/~davidb/mijson2/webrev.01

Best regards,

David