Add several natives for managing with class

[FortyTwoFortyTwo]

Several natives added:

• VScriptClass.SetScriptName
• VScriptClass.GetClassName
• VScriptClass.SetClassName
• VScriptClass.GetDescription
• VScriptClass.SetDescription
• VScriptClass.RegisterInstance
• VScript_CreateClass

"ScriptName" and "ClassName" are usually the same, but some can be different from eachother (e.g. CEntities as script and CScriptEntityIterator, as class, while Entities is actually used as a name in script).

vscript_test.sp have an example on how to create an instance to make use of it. string param in VScript_CreateClass can be anything, probably...... while string param in VScriptClass.RegisterInstance are actually used in script files to call functions, aka InstanceName.InstanceFunction(322).

No support yet for creating non-instance class for an actual entity class. That'll take more work and effort, so just instance will do for now.