HTTP Server: Fix If Modified Check

An extra unnecessary semicolon in the test was preventing the if modified from properly working at least on chrome.

Fixing this cuts down slightly on the amount of data that needs to be transmitted.  For most users this probably won't be noticed.
AJAX Server: Send Status Code Response When Closing an Empty Socket

The lack of a status code made it difficult to distinguish empty sockets from an unreachable server on the client end.

This adds a trivial, 25 bytes, amount of data to the transmission.
IA7/JSON: Change JSON Structure; Enable Updating in IA7

Added request and option to returned json to make recreating the request easier.

Added millisecond time to JSON response to allow for long polling.

Enable long polling in JSON.  If long poll is requested, the routine will return nothing if only an empty JSON would be returned.  In addition, the time parameter is used to skip objects which have not changed since time.  This used the idle_time value.