Copy generated library to the projectdir

.gitignore

@@ -3,6 +3,18 @@
 
 # Ignore library files but not the gdextension file
 demo/bin/*
+!demo/bin/android
+demo/bin/android/*
+!demo/bin/android/.gitkeep
+!demo/bin/linux
+demo/bin/linux/*
+!demo/bin/linux/.gitkeep
+!demo/bin/macos
+demo/bin/macos/*
+!demo/bin/macos/.gitkeep
+!demo/bin/windows
+demo/bin/windows/*
+!demo/bin/windows/.gitkeep
 !demo/bin/*.gdextension
 .sconsign*.dblite