switch headers + avoid duplicate definition

First I apologize to have broken gen-build... still don't really understand why this step is required... condtional buildtime option should be enough...

as 379c258 and d9ded2a are mostly enough to allow "100% free" build, this minor change allow

1/ to avoid both headers to be included in big phalcon.c

2/ allow to gen-build + build when non-free file are drop, as this step is mandatory for downstream distribution where non-free sources cannot even be part of the source.

See an exemple how this can be done for phalcon
https://github.com/remicollet/remirepo/blob/master/php/php-phalcon/strip.sh

P.S. perhaps you can even drop the js(css)minifier.h, and keep only one, without the "Douglas Crockford Fucking License"... (as this function prototype is obviously from Phalcon project not, from D.C.) but I don't want to touch any non-free source code.