Huge fucking commit. Made good progress towards a more packaged/modular form of the code. Also added a RootFile accessor which stores the data from the imported root file. This means we only have to read it once, and into memory -- so we're not strictly I/O bound. Completed initial stages of package. It is ready to be merged into master. Efficiency is broken for now.
Merge pull request #4 from kratsg/building-atlasjets-package

Repackaging code into a package
s/pixel/cell/g all files. Removed all code referring to isinstance() because if anyone misuses it, they're a fucking idiot. Mostly.