Log Message:
Update to 2.021

Upstream changes:
2.021     2014-02-20

    - Fixed numerous bugs in the string parsing code, including the
      one reported in [RT #63918] by Frank Doepper.

    - [RT #41049] Rewrote literal string parsing to prevent a stack
      overflow due to an inefficient regex (reported by Sergei
      Fetisov).

    - [RT #91822] Fix compression of GIF images to ensure that output
      codes don't exceed 12 bits (reported by Vadim Repin).

    - The RunLengthDecode filter didn't actually work.  Its code has
      been rewritten and now passes basic encoding and decoding tests.

    - Fix Code128 barcode switching from Code C to Code B in certain
      cases (reported by Doru Petrescu).