Add multipledispatch to dependencies on README
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This should've been in 0.6.2!!
Add scalar support to Vector3/4. Fixes #22.

Add support for +-*/ for scalars to Vector3/4.
Add scalar support to Matrix33/44. Fixes #23.

Add support for +-*/ to Matrix33/44 with scalars.
Add support for +- Matrix33/44. Fixes #24.

Add support for +- Matrix33/44 together.
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Bump to 0.6.3