Layout module enhancement

[hacketo]

Just started openscad with this awesome project, I added some features for the layout module that could be useful to the project.

Multiple legends : layout-legends-multiple

I had some issues with the recursive scope, just started openscad and I don't know how I can solve that ugly issue for the legends...

• font alignment : $font_align, $font_align_front
• font size : $font_size_front
• legends position : $legends_position, $front_legends_position
• updated doc for legends positioning doc
• example : layout_legend_multiple

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Spacebar 3u support: layout-3u-spacebar

• updated spacebar api to add key size and stab size, kept stab sizes to what already existed
• updated layout to handle 3u spacebar
• example : spacebar

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Progressive corner radius for rounded square: rounded-square-progressive-radius

• use a linear corner radius from bottom to top : $corner_radius_bottom
• example : rounded-corner-progressive-radius

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Cherry Home key bump / dish: layout-cherry-home-bump

• enable dish on Home keys (F-J) : $cherry_home_dish (false | number)
• enable bumps on Home keys : $cherry_home_bumps
• key bump width : $key_bump_width
• key bump radius : $key_bump_radius
• Detection based on column index..

[epicfacethe3rd]

i should note that 3u spacebar stabilizers don't really exist, so it's a good idea to change them to 2u stabs instead