Add DUK_NOINLINE for fixing GH-55
Avoid inlining duk__handle_longjmp() (GH-55)

Apparently inlining duk__handle_longjmp() messes up setjmp/longjmp variable
semantics and causes various issues with OSX (see GH-55 for symptoms).
Merge branch 'add-noinline-handle-longjmp'

Minimal fix attempt for GH-55.