convert razor_package_get_details() and razor_package_iterator_next() to varargs

The functions for getting package details about a package were limited to a few
things, when in the future we will want to support much more about a package.
The iterator was also limited to name,version,arch when most of the time we
didn't need all this data.

 ## Process this file with automake to produce Makefile.in

 pkgconfigdir = $(libdir)/pkgconfig

 pkgconfig_DATA = razor.pc

 bashcompletiondir = ${SYSCONFDIR}/bash_completion.d

 dist_bashcompletion_DATA = razor.sh

 clean-local :

 	rm -f *~