Building on the ideas from http://2e5.com/kite/parametric/
this library supports parametric CAD design based on polar vectors.

See http://en.wikipedia.org/wiki/Vector_notation#Polar_vectors

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Vision:
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The goal of this library is to emulate a manual design process. Doing the process
programatically instead of manually enables parametric design.

The key decision for this library is the correct choice of abstraction. Basing all
items on Polar Vectors allows great design freedom and concise design implementation
code.

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Testing:
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The file 'tests.txt' contain tests of all functionality in the library. In addition,
each time a design is created which relies on this library, it is a good idea to
add a design regression test file. This will ensure that future changes to the library will
maintain backward compatibility with existing usage.

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Todo:
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- implement "SmoothNotch()" bezier drawing code
- “inversion of control” or other pattern later on to abstract CAD program "draw()"
  command when need arises to target a 2nd CAD package