Add globalId servlet and misc fixes

- Add a servlet allowing Javascript code to retrieve the global id
(third-party cookie)
- Avoid generating sessions/user ids with leading spaces
- Adjust the display in live console (no word wrapping in User-Agent)
- Mix cosmetic fixes
Add a "/internal/flush" servlet to force a flush of the storage queue
Add a configuration parameter to flush the storage queue at a fixed time
interval
Modify the filesystem storage handler to use temporary files when
writing
Modify storage handlers so that they do not create empty files
Add explicit log messages on some invalid configuration parameters (to
be completed)
Make sure local config.properties files do not get included in wars