[WIP] Modeling income tax compliance

[jdebacker]

This PR adds two new parameters (labor_income_tax_noncompliance_rate and capital_income_tax_noncompliance_rate). These will allow the OG-Core model to account for the revenue and incentive effects of income tax noncompliance. Note that this is important since the tax function parameter are typically estimated using data that miss the effects of compliance (either because they use administrative data from tax returns or because of similar under-reporting in survey data (see Hurst et al. (REStat, 2014))).

This PR is a work in progress until the following items are addressed:

• [ ] test the tax.MTR_income and tax.ETR_income functions with non-zero noncompliance
• [ ] test tax.income_tax_liab function with non-zero noncompliance for the following combinations of parameterizations:
  • [ ] SS, j = None
  • [ ] SS, j!=None
  • [ ] TPI, j=None
  • [ ] TPI, j!=None
• [ ] test household.FOC_savings function with non-zero noncompliance for the following combinations of parameterizations:
  • [ ] SS, j = None
  • [ ] SS, j!=None
  • [ ] TPI, j=None
  • [ ] TPI, j!=None
• [ ] test household.FOC_labor function with non-zero noncompliance for the following combinations of parameterizations:
  • [ ] SS, j = None
  • [ ] SS, j!=None
  • [ ] TPI, j=None
  • [ ] TPI, j!=None
• [x] The tax noncompliance parameters are described in the documentation