Log Message:
Update ruby-sexp-processor to 4.9.0.

=== 4.9.0 / 2017-04-13

* 9 minor enhancements:

  * Added Sexp.depth
  * Added Sexp.sexp_type=
  * Cache Sexp.line_max. Massively speeds up large flay runs.
  * Cleaned up SexpProcessor.process handling of result node type.
  * Extend pt_testcase for ruby 2.4 tests.
  * Extended Sexp.method_missing to only print on every invocation if $VERBOSE=1
  * Extended Sexp.method_missing to warn if the expected sub-sexp is not found.
  * Rewrote Sexp.mass to be MUCH faster. Helps tremendously with flay on large files.
  * Warn that Sexp#method_missing was tripped if $DEBUG.