add GUNMASTER_WEAPONS_PRESET_BY_NAME and GUNMASTER_WEAPONS_PRESET_BY_INDEX mappings

gunMasterWeaponsPreset give a int back ( added on commit: 4b7537630e4dd96048c6c04e6f7852097829a3ba ...lets use it:
get preset name: GUNMASTER_WEAPONS_PRESET_BY_INDEX[1][0]
get preset weapons: GUNMASTER_WEAPONS_PRESET_BY_INDEX[1][1]
or get preset weapons list by name: GUNMASTER_WEAPONS_PRESET_BY_NAME['US arms race']