#43 Add a field in list of Data Types

[Randolf C. Richardson]

When managing the data types, if a user wishes to know
what is using a given data type they must right-click on it
and choose "Usage." This is a nice feature, but
becomes quite tedious to use when searching for unused
data types.

Adding a second column to the list of data types that
simply displays the number of times each data type is
used would be quite helpful in these situations (and make
for great ease-of-use eye candy for many other
situations).

- Randolf Richardson