Merge branch 'master' into jgrpp

# Conflicts:
#	src/CMakeLists.txt
#	src/network/network_server.cpp
#	src/network/network_survey.cpp
#	src/vehiclelist.cpp

src/script/api/script_industry.hpp

@@ -331,6 +331,7 @@ public:
 	/**
 	 * Gets the current production level of an industry.
 	 * @param industry_id The index of the industry.
+	 * @return The current production level of the industry.
 	 * @api -ai
 	 */
 	static SQInteger GetProductionLevel(IndustryID industry_id);