Deleted RtError.h from distribution and renamed all references to
RtError in the documentation, test files, and Windows .dsp files.
The version number was incremented to 4.1.0 in anticipation of
the next release, as this change affects the API.

including fix of MinGW ASIO compile problem (iasiothiscallresolver),
OS-X problem handling device names in some languages (CFString
conversion), small change to OS-X MUTEX lock location to avoid
lockups, and correction to documentation regarding 24-bit data (should
be lower 3 bytes, not upper 3 bytes).