Don't expose TypeWithDict property mask

In order to modify TypeWithDict so that it can handle types that are pointers or C-style arrays without header parsing, it is necessary to use additional bits in the property mask.
This means that user calls must not be allowed to arbitrarily set bits in the property mask.  The property mask is currently an argument to several public constructors of TypeWithDict.
For each such public constructor, this pull request either removes it or makes it private.  Only two lines of code outside the framework are affected/
Please merge this request as soon as convenient.