various updates

 # mod_ssl.h ............... common header file of mod_ssl

 # ssl_engine_config.c ..... module configuration handling

 # ssl_engine_dh.c ......... DSA/DH support

 - ssl_engine_ext.c ........ Extensions to other Apache parts

 # ssl_engine_init.c ....... module initialization

 # ssl_engine_io.c ......... I/O support

 # ssl_engine_kernel.c ..... SSL engine kernel

 SSL_EXPERIMENTAL_xxxx variables, except if SSL_EXPERIMENTAL_xxxx_IGNORE

 is already defined. Currently the following features are experimental:

   o SSL_EXPERIMENTAL_PROXY

     The ability to use various additional SSLProxyXXX directives in

     oder to control extended client functionality in the HTTPS proxy

     code.

   o SSL_EXPERIMENTAL_ENGINE

     The ability to support the new forthcoming OpenSSL ENGINE stuff.

     Until this development branch of OpenSSL is merged into the main

 o The complete EAPI-based SSL_VENDOR stuff was removed.

 o The complete EAPI-based SSL_COMPAT stuff was removed.

 o The <IfDefine> variable MOD_SSL is no longer provided automatically 

 o The complete SSL_CONSERVATIVE stuff was removed, i.e.,

   SSL renegotiations in combination with POST request are not supported

   unless the problem is solved again, but this time through layered I/O.

 MAJOR CHANGES 

 from Apache 1.3 and this mod_ssl version for Apache 2.0:

 o The DBM based session cache is now based on APR's DBM API only.

 o Introduced Filter logic (similar to mod_tls)

 o The shared memory based session cache is now based on APR's APIs.

 o SSL I/O is now implemented in terms of filters rather than BUFF

 o Eliminated ap_global_ctx. Storing Persistant information in 

   process_rec->pool->user_data. The ssl_pphrase_Handle_CB() and 

   ssl_config_global_* () functions have an extra parameter now - 

 o Properly support restarts, allowing mod_ssl to be added to a server

   that is already running and to change server certs/keys on restart

 o Various performance enhancements

 o proxy support is no longer an "extension", much of the mod_ssl core

   was re-written (ssl_engine_{init,kernel,config}.c) to be generic so

   it could be re-used in proxy mode.

   - the optional function ssl_proxy_enable is provide for mod_proxy

     to enable proxy support

   - proxy support now requires 'SSLProxyEngine on' to be configured

   - proxy now supports SSLProxyCARevocation{Path,File} in addition to

     the original SSLProxy* directives

 o per-directory SSLCACertificate{File,Path} is now thread-safe but

   requires SSL_set_cert_store patch to OpenSSL

 o RSA sslc is supported via ssl_toolkit_compat.h

 o the ssl_engine_{ds,ext}.c source files are obsolete and no longer

   exist

 TODO

 o SSL renegotiations in combination with POST request

 o Port all remaining code (code inside #if 0...#endif blocks)

 o Do we need SSL_set_read_ahead()?

 o Enable SSL extensions (ssl_engine_ext.c)

 o add configure check for SSL_set_cert_store to support per-dir

   SSLCACertificate{File,Path}

 o the ssl_expr api is NOT THREAD SAFE.  race conditions exist:

   -in ssl_expr_comp() if SSLRequire is used in .htaccess

    (ssl_expr_info is global)

   ssl_engine_dh.c, while the comment in ssl_engine_kernel.c says:

   "it is suggested that keys be changed daily or every 500

    transactions, and more often if possible."

 o ssl_var_lookup could be rewritten to be MUCH faster

 o CRL callback should be pluggable

 o init functions should return status code rather than ssl_die()