the webui can now be run from read-only directories

dp2data is resolved as:
- windows: %APPDATA%\daisy-pipeline
- oxs: ~/Library/Application Support/daisy-pipeline
- linux: ~/.daisy-pipeline

job results are stored under $dp2data/webui/local.results/
webui log are stored as $dp2data/log/webui.log
webui derby log are stored as $dp2data/log/webui-database.log
the webui "startui" (pure HTML page displayed before the actual webui has started) is copied to $dp2data/webui/startui and are passed environment variables from the start script that lets it know if the webui is already running before trying to start it, and a full path to the dp2data directory where the RUNNING_PID file must be deleted in some cases

the webui database is stored as $dp2data/webui/dp2webui and a clean copy of the database is copied there the first time the webui starts

uploads, as well as local mode temp files are stored under:
{system temp dir}/daisy-pipeline-webui-{temp-dir}.tmp/[uploads,local.temp]

notes on server mode:
 - uploads, local mode temp files and local mode results files are only configured in desktop mode. In server mode, these must be set manually.
 - the startui is also used only in desktop mode and is not included when deploying the webui in server mode
 - other than that, the database and log files should still be stored in $dp2data now even in server mode so the webui can be run from a read-only location in both desktop and server mode.


also:
 - the main webui log is rolling (daily or at 50MB)
 - a uninstall script is added for simple deletion of all user data (database, logs, job results)


tested in win7. some more testing remains...