API: Rename search to fullTextSearch

[ChangeLog][API] Renamed the search function to fullTextSearch

Change-Id: I4c667ccbf89048e9ef49d26d4fb80ed52153dfde
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
API: Rename downloadFile to downloadUrl

[ChangeLog][API] Renamed the downloadFile function to downloadUrl to
make it clear that this function does only provide a URL and does not
download the file.

Change-Id: I6b3c20de9319c7545ff266d2778b985729fe5077
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>