Add snipmate-compatible snippets to expand common syntax keywords

[sionleroux]

I made this list of snippets for the most commonly used commands to somewhat replicate the convenient completion you get when using the embedded OpenSCAD editor for Vim.

For example, type cube and press the snippet expansion mapping and it becomes cube([x,y,z]); with the cursor positioned on x and ready to jump to the next letters.

I can make a separate plugin if this is the wrong place but I've seen other syntax plugins including snippets and I think it would be convenient here, together with the current highlighting, commenting, folding rules etc.

[sirtaj]

I think including the snippets is ok, thanks for this.