lookup : removes the lock during a lookup

- search_entry stays always sensitive during a lookup. A spinner
notifies about an ongoing lookup. If the user activate the
search_entry during an ongoing lookup, the lookup is avoided and
the spinner is disabled.

- adds some space around the search entry.

Change-Id: I131bad09064f8f286fd00d97188d3c2e9264044b
Tuleap: #1295
2 files changed