Add missing "var" keyword to avoid implicit global variable usage.
Refactoring of the 'epub' module and package document parsing - phase 1:

* Variable and parameter naming consistency
* Move SMIL and package document parsing code from Readium.js to the 'epub' submodule
Merge pull request #30 from aadamowski/develop

Add missing "var" keyword to avoid implicit global variable usage.
Merge pull request #31 from readium/feature/epub-module-refactoring

Feature/epub module refactoring