Fixed broken HashSet test so they don't assume the elements are processed in order.
Imported SetType and SetModule tests from the F# source distribution. The test currently don't compile because HashSet is missing a few members/functions which still need to be implemented.
More progress on getting the SetType and SetModule tests working for HashSet.
Added ReaderState.read.
Removed duplicate IntSet.Delete method (simply use Remove instead).
In-progress work on rounding out the HashSet functionality.