plugin: (1,1) is implied
plugins: ignore sample_* and stub
plugin: add PluginBase.bind_texture

Makes PluginBase contain all methods that must be implemented.
plugin: fix PluginBase.render
plugin: use composition instead of inheritance
plugin: update opengl framebuffer class

based on nox4 entry
plugin: add init method

Runs after all attributes has been setup (and logging exists)
plugin: handle framerate = 0 properly
plugin: reset invalidation flag
core: smoother animation framerate
plugin: rudimentary shader support for opengl
plugin: move into subpackage
plugin: some short comments for base plugin
plugin: handle when shaders isn't available
example plugins
documentation
Merge branch 'plugin_misc'