Reordered headers.

We put our headers first to make sure that the preprocessor sees
our macros, defines and whatever else before external code.
Ensure that headers compile on their own.
Reverted tolerance to previous value.

The increased errors were due to a missing bug fix on the
development branch.
Modify a few test messages
Prevent a few VC++ warnings.
Drop support for Visual C++ 2003 (VC++7).

The compiler is now more than 10 years old and no longer supported
by Microsoft.  Keeping the support is not worth the time and effort
required.  Anybody who is still stuck with this compiler and needs
the support can fork the repository and maintain the changes.
Deprecated a couple of unused classes.