implement room database

.idea/caches/build_file_checksums.ser

app/build.gradle

...ava/me/szaki/xkcd/xkcdbrowser/XKCDBrowserApplication.java

...aki/xkcd/xkcdbrowser/XKCDBrowserApplicationComponent.java

...in/java/me/szaki/xkcd/xkcdbrowser/database/ComicsDAO.java

...va/me/szaki/xkcd/xkcdbrowser/database/ComicsDatabase.java

...ain/java/me/szaki/xkcd/xkcdbrowser/database/DBModule.java

...main/java/me/szaki/xkcd/xkcdbrowser/model/ComicStrip.java

...aki/xkcd/xkcdbrowser/ui/favorites/FavoritesPresenter.java

...java/me/szaki/xkcd/xkcdbrowser/ui/main/MainPresenter.java