Revert "inline not safe to use in czmq_prelude.h, removed"

This reverts commit fe7fbf84d28cda6d28f7539ed7583211680d8bd1.
Revert "Removed definition of 'inline' for Windows"

This reverts commit b703c6134b373750cc885d5fd300e15f0fdb0459.
Safer fix for issue #212