Organize lib targets

Order them lexicographically. Move junit and its private dependency
hamcrest into a subpackage.

Change-Id: I059541885144981a3ab9f605492243da71bba2d0

lib/junit/BUCK

diff --git a/lib/junit/BUCK b/lib/junit/BUCK
new file mode 100644
index 0000000..a2f4093
--- /dev/null
+++ b/lib/junit/BUCK
@@ -0,0 +1,13 @@
+maven_jar(
+  name = 'junit',
+  id = 'junit:junit:4.11',
+  sha1 = '4e031bb61df09069aeb2bffb4019e7a5034a4ee0',
+  deps = [':hamcrest-core'],
+)
+
+maven_jar(
+  name = 'hamcrest-core',
+  id = 'org.hamcrest:hamcrest-core:1.3',
+  sha1 = '42a25dc3219429f0e5d060061f71acb49bf010a0',
+  visibility = ['//lib/junit:junit'],
+)