add a simple example of usage

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darcs-hash:20130920201219-3a4db-8a41b04a2cc70aa325f80e7e628c58916d537cd4
README - add section on installation from PyPI

Ignore-this: 6f5aeb2c9ebbb9693aea42b633db1c99

darcs-hash:20130920201508-3a4db-ce9340fd6e3ad8a00f042a42f9606da23c48ed9a
prepare to release 0.1

Ignore-this: 15ef56a634cb5a894a2d92f13186de46

darcs-hash:20130920201707-3a4db-b321eeb00fb5306f1cba91ff82c44b6b8f04ef1e
start development of 0.2

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darcs-hash:20130920201815-3a4db-a68fe9b9f41718b2a7329a98182121b09dc926ab