Rename playlist and file browser classes

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
[docs] Add class and sequence diagrams

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Update class names in diagram

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Fix notification actions in KitKat

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Update changelog

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>