Add ability to set function name on php_function macro

[joehoyle]

This is much the same as php_class(name="ABC")

[striezel]

@joehoyle: You might want to rebase your changes on top of the current master branch to get rid of those clippy warnings. I guess the automated checks should pass then.

[joehoyle]

@striezel @ptondereau ok can do-- I wanted to check if anyone have merge capabilities though? As I wasn't sure how abandoned the project is right now. Are either of you happy / able to merge things?

[ptondereau]

For the moment, only @TobiasBengtsson have the merge right. But for us, we just review the PR.

[joehoyle]

@TobiasBengtsson ok this should be good now.

[TobiasBengtsson]

Thanks! It would be nice to have more maintainers in fact, since I don't have that much time. See #140 and email David if you're interested @striezel @ptondereau