Mortgage initialization parameters added

Init files version 1.0.4 are usable if you add these three lines to
environment:
<min_loanterm_at_start>25</min_loanterm_at_start>
<max_loanterm_at_start>40</max_loanterm_at_start>
<mortgage_cost_to_income_ratio>0.15</mortgage_cost_to_income_ratio>