core/Ref: added `init()` virtual function as initializer and removed …

…`SLIB_REFERABLE_CONSTRUCTOR`

graphics/Image: added `stretch()`, `stretchToSmall()`

sapp: support Android Studio on Windows

ui/View/Win32: fix non-invalidating issue when hide the top view

examples/sapp: minor update

Changed Readme

Update README.md

#24 Added bash files for creating new projects

error fix on ip address comparation

UI/GTK+: Support low version of GTK+2

fix errors on `UrlRequest`