Restructuring, removed premake4 dependency, removed embedded outdated glfw/glew

Makefile changed to by default compile a shared lib to be insatlled in usr/local
sample changed/updated to use GLFW3 (Currently my fork on deltaluca/glfw)

Removed GL2 renderer
Set buttons to have centered text, allow lebels to define alignment.
Allow labels not to move widget locations for successive draws.
Tweaks, add alignment to Value command.
Fix scrolling when changing window sizes back up again.