Defined more validations. Checking path existance, sound file existance and colorful notification. Only green bordered fields are stored in config (transparent)

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>
Improved instant use of changed sound file.

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>
Defined allowed file types editor in configuration widget.

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>
Defined plain text editor for file types.

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>