No EnvironmentDescription::hasProperty method

[ptheywood]

Unlike AgentDescription, which provides methods to check if an agent description has alreadyu been created a new Varaible by its' string name, Environment does not have a corresponding hasProperty method.

It can be checked with a try catch around a call to getProperty, but a bool returning version would be good for concistency with AgentDescription.

FLAMEGPU2/include/flamegpu/model/AgentDescription.h

Lines 134 to 138 in 4e02604

	/**
	* @param variable_name Name of the variable to check
	* @return True when a variable with the specified name exists within the agent
	*/
	bool hasVariable(const std::string& variable_name) const;