Pre-Release 0.9

This release marks a point of improved maturity in the codebase. Though still lacking any functional tests, the bot is split into classes in separate modules and has a minimal level of abstraction protecting various pieces of code from each other, and separating concerns (such as worksheet searching) from specific use cases (such as finding an esper or finding a unit, using worksheet searching). Configs for the bot itself are carved off from configs for the stub that actually launches the bot. Constants and common classes are pulled into their own files. Globals are eradicated except in the bootstrapping stub, and the Google Spreadsheets access object is persistent throughout the lifespan of the bot instance. Imports are cleaned up and pylint warnings have been addressed.

In short, the code is now in a state where creating tests makes sense. This will be the next significant step forward.