it's probably a good idea to save all files before committing.
more unused using statements removed.
Renamed ArgumentTests.IsOf to ArgumentTests.IsOfType to match
a previous renaming of the method being tested.
Added exception message when trying to compare two incomparable types.
Add overload for EnumerableArgumentExtensions.IsNotEmpty that takes a custom
message for the exception.
Add xml doc comment for the ClassArgumentExtensions.IsNotNull overload
with the custom message
Bad xml doc comments are bad.  changed type parameter from
TStatement to T.
added custom message overload for GuidArgumentExtensions.IsNotEmpty
Adding doc comments to the GuidArgumentExtensions.IsNotEmpty overload with
custom message.
Also adding message param comment to other doc comments that were missing it.
Consistency in formatting of type parameter constraints
Adding overloads with custom messages for String argument methods
Merge branch 'release/0.9.1'