Output every Java class, including the support classes, from gobind
-lang=java. In addition, replace Go package export data parsing with
converting from go/ast to go/types. That way, gobind can tolerate
unknown imports as long as the exported Go API doesn't use them.
In a follow-up CL, the gobind gradle plugin will use gobind for a first
pass to expose the generated Java classes to the android plugin.
Change-Id: I8134899ec818c7fee79e4d9df8afcae9dd679add
Reviewed-on: https://go-review.googlesource.com/30093
Reviewed-by: David Crawshaw <crawshaw@golang.org>