[Tizen] Remove method set_path from ApplicationData class

Method set_path from ApplicationData class is deleted.
Function in which it was called has been refactored.

BUG=XWALK-2926
[Tizen] Fix allow-navigation WGT configuration element handler unit test

This patch adds unittest_util.h/cc in manifest_handlers directory, which
introduces a simple way for default W3C and WGT widget configuration creation.
Merge pull request #2615 from sstolinski/sstolinski

[Tizen] Remove method set_path from ApplicationData class
Merge pull request #2617 from tweglarski/AllowNavigationUnitTestFix

[Tizen] Fix allow-navigation WGT configuration element handler unit test