Use HTTP::Server::Simple, RT#95223.

This now passes on OpenBSD.
Use BEGIN block to skip tests in no HTTP::Server::Simple
Put HTTP::Server::Simple into inc/ so tests can run

t/83-attachments.t uses this module which is not always installed.
It is good to always run this test, though, so we include
HTTP::Server::Simple into the distribution.
Fixed one-line comment describing the script.
Support custom fields with '#' in their name.

Patch contributed by Ryan Niebur in RT#83856.
All parts of this module now under Perl Artistic License.

GPL is gone.  This was done with permission from the original author
of the command-line `rt' utility, Abhijit Menon-Sen.
Fixed a couple of comments -- no code changes.
80-timeout.t now correctly runs on Windows
Merge branch 'master' of https://github.com/dtikhonov/RT-Client-REST
81-submit.t now correctly runs on Windows
82-stringify.t now correctly runs on Windows
83-attachment.t now correctly runs on Windows
Commented out diag message: a bit too verbose
Documented get_links() -- RT#68673.
Version 0.49
Merge pull request #4 from dtikhonov/master

Version 0.49 is out -- see CHANGES for details.