Adding BatchType and ChartType helper classes to convert string inputs to enums

[longpshorn]

Not sure whether these below in the IEXSharp library or not, but as I am developing my client that is making use of the library, I wrote these helper methods and thought they might be beneficial to have in the library.

I can pull them out if you don't think it would be appropriate to add them, but I thought they could potentially be a benefit to others as well. What do you think?

[longpshorn]

If you think this makes sense, I will add similar methods for other enums as well.

[vslee]

I did not think about the case where people might want to convert back from a description to an enum. It seems like a lot of work to go through all of the enums and write mirror methods for each one. It might also introduce a little bit of brittleness where if the description changes, two places in the code now have to be updated (although the that's probably just a minor nitpick). What do you think if, instead, we introduced a method such as this:

		public static TEnum GetEnumFromDescription<TEnum>(this string stringValue)
		{
			var enumType = typeof(TEnum);
			var members = enumType.GetMembers();
			foreach (var member in members)
			{
				if (member.GetCustomAttributes(typeof(DescriptionAttribute), false)
				.FirstOrDefault() is DescriptionAttribute descriptionAttribute
				&& descriptionAttribute.Description == stringValue)
				{
					return (TEnum)Enum.Parse(enumType, member.Name);
				}
			}
			throw new Exception("Description string not found.");
		}

Note, that is just the top of my head, I have not tested that code yet. It may need some modifications to work properly.

[longpshorn]

Yes, this makes more sense. I agree that it my approach was a bit brittle. It was admittedly just a bit of a quick hack to get it working for my use case so I appreciate your thought on this. I will take a look at adding it and making sure it works as expected.