add show_content_type()

Spy on content type for character-encoding hints
use strstr() to check for "www-url-encoded" in content-type

rather than strcmp. Also, add "responder" alias for "http".
create session data store only on demand

not automatically, to avoid storage waste
embed session store functionality

KyotoCabinet calls specialized for session storage management

session-read - read entire session store
session-get - read specific session variable
session-set - set specific session variable

Also, every "set" operation writes a timestamp to the session store, for later
clean-up.
fix interpretation of mktime() result

If error in mktime, result is exactly -1. Other negative results are
valid for time before 1/1/1970.
add pg-cmd-tuples, for count of non-select tuples affected