Adding Demo (and some minor editor features)

[dgm3333]

Adding Demo (and some minor editor features)

This adds a demo with an image on the readme and instructions on how set it up
Adds some extra class functions and class variables as well as an enum for some of the demo features

inline void setLastSaveTime(uint64_t lastSaveTime = 0) { mLastSaveTime = lastSaveTime; }
inline uint64_t getLastSaveTime() { return mLastSaveTime; }
inline void setAutoSaveInterval(uint64_t autoSaveInterval = 0) { mAutoSaveInterval = autoSaveInterval; }
inline uint64_t getAutoSaveInterval() { return mAutoSaveInterval; }

inline void SetFilename(const std::string& aFilename) { mFilename = aFilename; }
inline std::string GetFilename() const { return mFilename; }

void MoveTo(const Coordinates& aPosition);
void SetFind(const std::string& aFindStr) { mFindStr = aFindStr; }
void Find();

inline void drawLineNumbers(bool dln = true) { mDrawLineNumbers = dln; }
bool mDrawLineNumbers = true;

uint64_t mLastSaveTime = 0;
uint64_t mAutoSaveInterval = 5;
std::string mFilename;
std::string mFindStr;

bool mNeedsInit = true;

enum textEditorFlags
{
textEditorFlags_None = 0,
textEditorFlags_NoStatusBar = 1 << 1, // Disable the status bar
textEditorFlags_StatusBarTop = 1 << 2, // Status bar on Top (else at bottom)
textEditorFlags_NoMenuBar = 1 << 3, // disable the menu-bar
textEditorFlags_ReadOnly = 1 << 4,
textEditorFlags_ReadOnly_OnceOnly = 1 << 5,
textEditorFlags_NoOpen = 1 << 6, // disable open
textEditorFlags_NoSave = 1 << 7, // disable save
textEditorFlags_AutoSave = 1 << 8,
textEditorFlags_NoQuit = 1 << 9, // disable quit
textEditorFlags_NoLineNumbers = 1 << 10, // don't display line numbers