If 'search-enabled' attribute is missing, use value, defined in 'uiSelectConfig.searchEnabled' instead of hard-coded 'true'
Added tests to check behaviour of searchEnabled option of default config object.
Merge pull request #325 from ravensteel/master

If 'search-enabled' attribute is missing, use value, defined in 'uiSelectConfig.searchEnabled' instead of hard-coded 'true'