7.0 l10n ca hr payroll

Added Canada income tax deductions and employee benefits. 
Corrected the canadian salary rules and added missing rules. 
Removed unused fields in hr.employee.
Please put one model per xml file and name the file after the model as it is easier to maintain that way.
i.e.: ` l10n_ca_hr_payroll/data/hr_deduction_category.xml`