Song from π

It's inspired by [Song from π! ](https://www.youtube.com/watch?v=wM-x3pUcdeo) and based on [Sheet music bracelet](http://www.thingiverse.com/thing:1580580).

Just input digits of π. The customizer will translate digits into notes. The period symbol of π is mapped to a crotchet rest. Here is the complete map.

num_to_note = [
[".", "4:br"],
["0", "#:g1,4:g1"],
["1", "4:a1"],
["2", "4:b1"],
["3", "4:c2"],
["4", "4:d2"],
["5", "4:e2"],
["6", "4:f2"],
["7", "#:g2,4:g2"],
["8", "4:a2"],
["9", "4:b2"]
];

The more digits you input, the higher pen holder you get. For examples, [song_from_pi.stl](http://www.thingiverse.com/download:3108728) is generated by 3.1415926535897932384626433832795028841971693993751058209749, and [song_from_pi_2.stl](http://www.thingiverse.com/download:3108729) is from 3.141592653589793238462643383279502884197169399375105820974944592307816406286 208998628