see description

- fixed bug "Every time when screen rotates OffersReceiverTask restarts"
(solution is in the onOfferTypeChanged() method check if selected offer
type equals to previous offer type, and if they are equal then do
nothing;

- fixed bug "Defining Actual and Past Offers" (cause of the bug was that
in xml file date field in offer entry was incorrect - year was present
as "14" instead of "2014", so all not-special offers was present as Past
Offers);

- Sort All Offers in order:  Special Offers -> Other offers in
descendent order by date field TO;

- fixed bug with displaying notify message about base location change.
Now the message is displaying only on long click on map and on click on
the "dismiss base location" button;

- mini-refactoring;