Many tweaks and bug-fixes throughout. build system got a number of tweaks to facilitate the plugin system, mostly --no-as-needed declarations on plugins so that they know how to load up dependent shared objects. Updates NEUT input handler and weighter. Begins adding support for the GeneratorManager which will help generator-dependent plugins know if they can 'safetly' get ahold of the original generated event or not. Adds nuisstudy, like nuiscomp, but for SimpleMCStudies.