RFR: 44: GitHubApplication should not use a JSONParser instance

[Erik Duveblad via github.com]

Hi all,

a `JSONParser` instance is not thread-safe and it is therefore a little dangerous to create instances of it _if_ that instance might end up being accessible by multiple threads. We have such a case in `GitHubApplication`. Since a `JSONParser` is very cheap to allocate (it only has an `int` and a pointer) I decided to make `JSONParser` package private thereby forcing all callers to use `JSON.parse`.

Thanks,
Erik

## Testing
- [x] `sh gradlew test` on Linux x86-64

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Commits:
 - 19e23934:	44: GitHubApplication should not use a JSONParser instance

Pull request:
http://git.openjdk.java.net/skara/pull/30

Webrev:
https://openjdk.github.io/cr/skara/30/webrev.00

Patch:
http://git.openjdk.java.net/skara/pull/30.diff

Fetch command:
git fetch https://github.com/openjdk/skara.git pull/30/head:pull/30