Rewrote AGWA code to 'wrap' Wayback replay URLs

Added wayback.url property to agwa.properties.

New Javascript function getReplayUriRef(url) returns the portion
of the replay URL which is (now, but wasn't always) common to
AGWA and Wayback, i.e. the /timestamp/archivedUrl part.

makeAgwaReplayUrl is redundant and agwaReplayUrl now simply grabs
the replay URI reference from the url passed in as its sole argument
and appends the URI onto agwaUrl (derived from agwa.url property
in agwa.properties).

Updated Toolbar.jsp to use an anonymous function to set up
config properties from agwa.properties in line with code in
HTMLError.jsp.

Removed redundant postMessage call from displayInNLAWebArchiveGUI()