Draw, ...: use "auto" for LKSurface::SelectObject() return value

Prepare for using a different return type, one that is lighter.
Screen/LKSurface: return raw WIN32 handles from SelectObject()

Eliminates the overhead for creating temporary LKFont/LKBrush/LKPen
instances.  The executable size shrinks by 34 kB.
Merge pull request #10 from MaxKellermann/linux

Reduce LKSurface::SelectObject() overhead
fix several "maybe unitialised" warning. (false positive)
replace TCHAR by char for profile file token, : avoid char to wchar convertion.
fix MainWindow SetFocus when App is Activate & other small improuvement.
- _hWnd is not set before OnCreate call.
- Add Sublass Window for Allow to create stock WNDCLASS
LKWindowSurface : fix false positive assert
Message : Use HWND wrapper class