PHP 5.2 Support and Misc. Bug Fixes

Most changes are explained well enough in the commit.  The only thing I wanted to clarify was the default formula added to expand_eq().

While I was debugging I noticed that some cells returned NULL even though they contained values.  I discovered that the  cells returning correctly had been previously used in a formula and their values where saved in 'staticvals'.  In order to ensure a cell would return it's contained value, I added a default formula pointing to the current cell.  That way the cell's value would be added to 'staticvals' and returned if a formula wasn't given.