Update test environment directory status

The test environment directory status (test case, test suite) depends on existence of files test and suite in the test environment directory. In case of test file exists, the directory is supposed to define a test case. In case of suite file exists (but no test file), the directory is considered to be a test suite directory. When test and suite files do not exist, the directory is considered to be any other test environment directory.

The test environment directory status is reflected in database directory entries in attributes test and suite. When the files have been changed in the file system, the status in the database is automatically updated only for entries selected in the tree. In order to update directory status for all entries, this action may be called. After updating directory status, Refresh action should be called via context menu for updating tree colors.