ZEND_ADD_STRING patch

For those who came to Dan & my or Derick's talk at the Int. PHP Conference, we both covered the bad inefficiency in the parser that results in strings with variables in them being tokenized on whitespace. This results in a huge number of unnecessary opcodes in strings. Attached (hopefully, as my new MUA seems to be fickle) is a first shot at a fix to the parser to keep this from happening, so that you don't need an optimizer to clear up this issue. I've tested this locally. It still introduces a single unnecessary opcode after variable in certain cases, but it works for me. George