Removed if/octopus_defs.h from public header file.

Removed if/octopus_defs.h from public header file.

Referenced in definitions.h and trigger.h.

trigger.h is problematic because it provides helper functions for
types definied in the interface. Clients that want to use trigger.h
now have to make sure to include the interface file.

Signed-off-by: Gerd Zellweger <mail@gerdzellweger.com>