BolProp and FlagProp should have explicit values for False

[eeverman]

The BolProp and FlagProp both currently compare a set value against a list of known true values (e.g. 'true', 'yes', 'on', etc.). All other values are considered false.

Thus, values like Yess, Truly, Truee, etc., are all be considered false without any sort of error or warning. This breaks the basic contract of AndHow, which is strong typing and validation.

Describe the solution you'd like
There should be a explicit list of false values so that validation is meaningful for boolean values. the list can be the converse of the 'true' list.

The logic for this should be moved into the BolType and not delegate to the TextUtil. TextUtil provides some basic text utilities, but the logic of how Strings are turned into values should really be in the Type classes.

Note: This is a behavior change and should be noted in the release notes and docs.

[eeverman]

Fixed in #729