Update Parameters

This PR updates parameters through 2015 and indicates which params should be indexed to inflation (see #72). 

Parameters that should be indexed to inflation are indicated by the annotation `(CPI-U)` in parameters.py.  

@feenberg, could you please check that I did not miss any parameters that should be indexed. 

@feenberg, also note that there are many parameters for which the 2013 values in the SAS file did not match the values reported in Young or similar sources. These instances are indicated with the annotation `UPDATE SAS`. 

We will need to update the gold-standard results files after this PR has been reviewed by @feenberg and others. 

I will be submitting an additional PR that makes the structural changes to calculate.py necessary for tax law changes between 2013 and 2024. @talumbau, please let me know if that is not the best course form a git perspective.