#58 Separed game menu enum from games definition, refactored application texts

core/src/cz/nic/tablexia/Tablexia.java

core/src/cz/nic/tablexia/TablexiaSettings.java

core/src/cz/nic/tablexia/game/GameDefinition.java

...c/tablexia/loader/application/ApplicationTextManager.java

core/src/cz/nic/tablexia/loader/zip/ZipAssetLoader.java

core/src/cz/nic/tablexia/menu/game/GameMenuDefinition.java

core/src/cz/nic/tablexia/menu/game/GameMenuItemGroup.java

core/src/cz/nic/tablexia/menu/main/MainMenuDefinition.java

core/src/cz/nic/tablexia/screen/gamemenu/GameMenuAssets.java

core/src/cz/nic/tablexia/screen/gamemenu/GameMenuScreen.java

...c/cz/nic/tablexia/screen/statistics/StatisticsScreen.java