finished #14252 http://redmine.ruswizards.com:8100/redmine/issues/14252
renamed receiver class
added final attribute to constants
submit changes from
https://github.com/eteplyakov/android_labs_rw/pull/13
Merge pull request #14 from eteplyakov/RM_14252_Lab_level_2_Battery_ringer

RM14252 - Lab level 2. Battery ringer