[plugins] director: shaper token allocation cleanup
[http] flow API: added read-property `req.query`.

will return the request query args
[plugins] director: minor code cleanup
[base] LogMessage: fixed isDebug()
improved debug logging and log message filtering / highlighting.

This is to help improving debugging sessions.
It introduces the optional environment variable XZERO_DEBUG
that can contain a colon seperated list of tag specifications
used to only show debug messages of that tag name, its
optionally defined verbosity level and in its optionally
specified ANSII color (helpful when logging into a terminal).

If no XZERO_DEBUG is specified et al but logging debug was requested
(via --log-severity), then every debug message is logged.

Example:

    XZERO_DEBUG="worker/3/green:director/10/white:director-cache/10/bold/yellow/bg-red:misc"
    export XZERO_DEBUG
    ./src/x0d ...