Option to test a local BouncyCastle jar (#16)

Resolves Github issue #4
diff --git a/WORKSPACE b/WORKSPACE
index 800d7ce..869307b 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -97,3 +97,7 @@
     name = "spongycastle_prov_1_54",
     artifact = "com.madgag.spongycastle:prov:1.54.0.0",
 )
+
+load(":local_repository_defs.bzl", "local_jars")
+
+local_jars(name = "local")