Log Message:
Update to 2.13:

+ Version 2.13 (12.05.2015)

  - Added support for offsetof() the way gcc implements it (special builtin
    that takes a type as an argument).
  - Added faked va_* macros (these are expected to come from stdarg.h)
  - Added a bunch more fake headers and typedefs to support parsing C projects
    like Git and SQLite without modifications to pycparser.
  - Added support for empty initializer lists (#79).