Synopsis - Issue Tracker

The C parser fails with a Segmentation Fault when called on an empty file:

$ touch empty.c
$ synopsis -p C -f HTML -o html_C empty.c

The attached patch handles this case.

There are really two issues:

* The C (and Cxx) parsers need to deal with
  an empty input. That's what your patch
  addresses, and that happens to be already in
  the current code.

* The preprocessor didn't use to handle
  errors. That I just fixed, i.e. a failure
  in the Cpp parser will raise a 'Processor.Error'
  now.

Current trunk throws an (IMO invalid) error for empty C and Cxx files:

$ > empty.cc
$ synopsis -p C -o empty.C.syn empty.cc 
Error: ParseError: The input contains errors.
$ synopsis -p Cxx -o empty.Cxx.syn empty.cc 
terminate called after throwing an instance of 'std::runtime_error'
  what():  The input contains errors.
Aborted