gui: simplify blanktimer

- get rid of separate thread, check timer in rendering thread instead
- use an enum for the blanking state instead of magic integers
- move #ifdefs for TW_NO_SCREEN_TIMEOUT inside blanktimer class
- move some #includes and enum TOUCH_STATE to pages.hpp

Change-Id: Id4b104e3680dc5db41d8ba85e32d722cf4086299

data.cpp

@@ -73,9 +73,6 @@ map<string, string>                     DataManager::mConstValues;
 string                                  DataManager::mBackingFile;
 int                                     DataManager::mInitialized = 0;
 
-#ifndef TW_NO_SCREEN_TIMEOUT
-extern blanktimer blankTimer;
-#endif
 extern bool datamedia;
 
 pthread_mutex_t DataManager::m_valuesLock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER;