Added unit test for getPrefix method
Remove unused code
Added unit tests for some Str methods (lower, upper, limit, length methods.)
Merge pull request #5804 from lucasmichot/dead-code

[4.2] Database : remove unused code
test values changed
Fix validator docblock
make LogTransport work with custom implementations of PSR LoggerInterface
Remove last duplicate unset
Extract file validation method
Query grammar should not explode segments on alias
ease saving of models without updating timestamps
Remove useless $app arguments in bindShared
Add getJsonOptions to JsonResponse
Add JSONP function to reponse facade
Made dependencies stricter
Only propagate the touchOwners call if a relationship exists
Remove extra newlines
fix memory leak in QueryBuilder/JoinBuilder
Fix the forgetMiddleware call (to not use get_class)
Another newline