Variable minHeight and option to hide inspector variables

[wilsnat]

"Help box does not include extra space if Icon is set to None and added an option to completely obscure the variable with a second constructor. This is useful if you want text at the bottom of your inspector"

Basically I wanted to have small notes about the component at the top and bottom of the inspector and this allowed for tighter boxes as well as not needing a visible variable to show it.

#if UNITY_EDITOR
    [SerializeField]
    [Help("This is a system component and is to be used with the TagSystem.", true, MessageType.None)]
#endif
    bool emptyBool = true;

the result is a single line help like this: