A bit of refactor to GraphicsRenderer
Bring back the unfinished Graphics
More work, lines are rendered wrongly
fix a few problems (close the paths when needed mostly)
Fix closing paths once and for all (hopefully)
Fixes the default stroke alpha to 1 if it's null.
Compile fix
Draw the line colors correctly
Added drawTriangles, it isn't optimized and doesn't support colors yet.
Added color support and a bit of optimization, still WIP
Only upload the tile buffer if needed
Merge branch 'master' of https://github.com/openfl/openfl into ogl_drawtriangles

Conflicts:
	openfl/display/Graphics.hx
Optimize a bit the Graphics drawing (remove some redundant calls)
Use BitmapData for Bitmap filling
Optimize drawTriangles. It's a work in progress:
- Changed LineStyle from an anonymous object to a class (there was a lot
of Reflect before)
- Optimize opengl calls so it won't repeat redundant ones.
- Calculate the object Matrix in the CPU side and not the GPU
- Changed drawElements to drawArrays (one less buffer to fill/bind)
Merge branch 'master' of https://github.com/openfl/openfl into ogl_drawtriangles
Fixing a few things:
- PatternFill shader uses the alpha
- SpriteBatch uses a bigger buffer
- Fixed drawTriangles uvtData if it is null
- Fixed drawTriangles culling
- Commented out GraphicsRenderer opengl caching, it has to be a global
thing for it to work right
Fixed bitmap pattern matrix relation to the object position
Enable the stencil buffer if openfl-next or webgl are enabled
Added a simple cache system.
If the object has `cacheAsBitmap` as true, it will first be drawn to
a framebuffer and then passed to the spritebatch to be rendered. It's a
pretty simple one, there can be more improvements to be done.