Reworked StringListBinding to take a list of optional string bindings.
Added ConditionalBinding.
Added ConstBinding.
StringListBinding, ConditionalBinding and ConstBinding can be combined
to do what the old StringListBinding did.
Revorked StringListBinding, renamed it StrngsBinding
Added string function that can build a string from a list of string
bindings.
Bootstrap simpleProgress.
ConstOrBinding
Added method to handle ConstOrBinding in RootBindingBuilder
Renamed type alias ReadBidning to ReadOnlyBinding
Removed unused import
Small bootstrap example mod