check for latest stable and development versions on startup, log info to...

... serverStartup.log

The user-agent for TDS looks like this:

User-Agent: TDS_4.5.2-SNAPSHOT-20140807.1055

Two new lines in serverStartup.log (first was already being logged):

2014-08-07T13:00:34.589-0600 [ 15327][ ] INFO serverStartup: TdsContext version= 4.5.2-SNAPSHOT - 20140807.1055

2014-08-07T13:01:26.473-0600 [ 67211][ ] INFO serverStartup: TdsContext latest development version = 4.5.1

2014-08-07T13:01:26.473-0600 [ 67211][ ] INFO serverStartup: TdsContext latest stable version = 4.2.22