TLS: OpenSSL Tcl Extension

This report covers two issues regarding the usage of the TLS package with
Tcl:

- empty reads when channels are readable according to [fileevent];
- stalling data transport for specific cases;

Please see attached file "tls_issues.tar.gz" which holds the detailed
description of the issues, as well as scripts that exercise and identify
these issues at the script level.

The exercisable setup was isolated from a more real-world, and compound
setup which utilized HTTP.

Thanks also to Alexandre Ferrieux for his help, especially with the strace
inspection.

We (Alex and I) feel that we've stretched our efforts as far as they are
efficient.

Since I can't tell which of the two (Tcl or TLS) can be held responsible,
this report has been cross-filed at the Tcl tracker as a reference.