Use string literal in reflection for compatibility with MCPC+. Fixes #71

getDeclaredField() with a string literal allows this field reflection
call to be properly remapped in MCPC+ to the actual field name. Fixes
java.lang.NoSuchFieldException: type
at uk.co.jacekk.bukkit.baseplugin.v10_1.util.ReflectionUtils.setFieldValue(ReflectionUtils.java:47)
error on /mv create skylands.