devel/dragon: update 1.5.0 -> 1.5.1

• Fix in src/Main.cc and samples/gxmain-master.cc. Include of stdlib.h added, since this is needed for Linux compiles ( exit function )
• In GoLangGenerator.cc scanner code was added to complete scanner state machine ( there still was missing some code for transition jumps )

Submitted by: Bjoern Lemke <lemke@lemke-it.com>