Add google-style checker to "arc lint"

Summary:
After we reached a consensus on code format, which follows exactly
Google's coding style, a natural follow-up is to have a style checker
that can handle stuffs beyond format.

Google already has a powerful style checker "cpplint.py" and,
luckily, phabricator already provides the built-in linter for it!
Next time with "arc lint" most style inconsistency will be detected
(but will not be fixed).

Also I copied cpplint.py to linters directory, which is mostly
because we may need the flexibility to make some modifications on
it for our own need.

Test Plan:
ran arc lint table/block_based_table_builder.cc to see the amazing
results.

Reviewers: haobo, sdong, igor, dhruba

Reviewed By: haobo

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15369

Author: liukai

.arcconfig

@@ -1,10 +1,11 @@
 {
-  "project_id" : "leveldb",
+  "project_id" : "rocksdb",
   "conduit_uri" : "https://reviews.facebook.net/",
-  "copyright_holder" : "",
+  "copyright_holder" : "Facebook",
   "load" : [
-    "linters/src/"
+    "linters"
   ],
   "lint.engine" : "FacebookFbcodeLintEngine",
-  "lint.engine.single.linter" : "FbcodeCppLinter"
+  "lint.engine.single.linter" : "FbcodeCppLinter",
+  "lint.cpplint.prefix" : "linters"
 }

.gitignore

@@ -20,3 +20,4 @@ util/build_version.cc
 build_tools/VALGRIND_LOGS/
 coverage/COVERAGE_REPORT
 .gdbhistory
+.phutil_module_cache