remove memory leaks
add unload JSONModule API
add Object.==, Object.!=
update mandelbrot sample code
Merge FuelVM
update stardate.h
fix CMakeLists
fix position of UnloadJson API
add Json.keys()
fix Json.keys() test
Merge pull request #349 from myoan/stable

add Json.keys()
add ResultSet.getBoolean()
Merge pull request #351 from nikuuchi/sql

add ResultSet.getBoolean()
Merge remote-tracking branch 'upstream/stable' into dtest
fixed dtest_glue.k