Update Buck to newest version

The new Buck version fixed macro resolution in cross-cell context: [1],
[2]. Moreover, new version includes number of performance improvements:

* parallel BUCK file parsing
* spooling Java class files directly to jar, without intermediately
 storing them on disc

Currently these features are not activated by default, so we have to
manually turn them on.

[1] https://github.com/facebook/buck/issues/544
[2] https://github.com/facebook/buck/commit/d2cffbd60d3252d2025394e7c92c5ef2f272e271

Change-Id: I133347ad7e963107bea637ece6cd3ee80842d802
diff --git a/.buckconfig b/.buckconfig
index c766d30..7814eec 100644
--- a/.buckconfig
+++ b/.buckconfig
@@ -21,10 +21,12 @@
   includes = //tools/default.defs
 
 [java]
+  jar_spool_mode = direct_to_jar
   src_roots = java, resources
 
 [project]
   ignore = .git, eclipse-out
+  parallel_parsing = true
 
 [cache]
   mode = dir