several small changes and fixes

The flyspray image is default logo image now.
Fix to install files so the logo can be saved.
Bulk edit now still have filtered search result after submit rather than all result.(changed tasks that do not fill the terms will not be shown)
When creating a new task, will check with the server first for same tasks and let user confirm if still need to create.
An error of wrong address for bulk create has been fixed.
An error for new task creation has been fixed. The summary is trimmed so that a blank but not empty summary would not skip check.