Create gradle build

Replaces the make build. Uses bintray to supply the repoindex cli.

Fixes https://github.com/bndtools/bundle-hub/issues/12
Merge pull request #13 from bjhargrave/gradle-build

Create gradle build
Update repo with updated Felix bundles

Framework, Gogo command & runtime, and HTTP Jetty

Signed-off-by: Sean Bright <sean@malleable.com>
Merge pull request #8 from seanbright/felix-updates

Update repo with updated Felix bundles