tweaked renderer error handling

improvements:
*  got html out of errors in non-html renderers (though those errors should probably eventually go to views, too)
*  made it so rescue happens from #_render (not just #render)
*  moved actual rescue handling into new method outside of #_render so (a) it can be customized, and (b) it's not repeated in every single view method def
*  specified :rstar=>true on rstar-specific sets
*  fixed misleading spacing on alias_view