Fix constant in VAR and PAC expectations...

matlab/+pac/+update/parameters.m

matlab/+var_expectation/update_parameters.m

matlab/get_companion_matrix.m

matlab/print_expectations.m

matlab/write_expectations.m

tests/var-expectations/1/example1.mod

tests/var-expectations/2-with-time-shift/example1.mod

tests/var-expectations/2/example1.mod

tests/var-expectations/3-with-time-shift/example1.mod

tests/var-expectations/3/example1.mod

tests/var-expectations/4-with-time-shift/example1.mod

tests/var-expectations/4/example1.mod

tests/var-expectations/5-with-time-shift/example1.mod

tests/var-expectations/5/example1.mod