documentation work-in-progress
Added inline documentation
small inline doc fixes.
added documentation.md and edited README.md
small changes in docs
small updates
Merge remote-tracking branch 'origin/docs' into cocos2dx-v3

Conflicts:
	Soomla/CCEventHandler.h
	Soomla/CCIStoreAssets.h
	Soomla/CCSoomla.h
	Soomla/CCSoomlaJsonHelper.h
	Soomla/CCSoomlaNdkBridge.h
	Soomla/CCStoreController.h
	Soomla/PurchaseTypes/CCPurchaseWithVirtualItem.h
	Soomla/data/CCStoreInfo.h
	Soomla/domain/CCMarketItem.h
	Soomla/domain/CCPurchasableVirtualItem.h
	Soomla/domain/CCVirtualCategory.h
	Soomla/domain/CCVirtualItem.h
	Soomla/domain/virtualCurrencies/CCVirtualCurrencyPack.h
	Soomla/domain/virtualGoods/CCEquippableVG.h
	Soomla/domain/virtualGoods/CCLifetimeVG.cpp
	Soomla/domain/virtualGoods/CCLifetimeVG.h
	Soomla/domain/virtualGoods/CCSingleUsePackVG.h
	Soomla/domain/virtualGoods/CCUpgradeVG.h
fix merging error
fix deprecated code