Use rounding for treatments

[wenzeslaus]

Replaced flooring by rounding in all treatments.

• PR in rpops with this change Use rounding for treatments rpops#203
• PR in r.pops.spread with this change Use rounding for treatments r.pops.spread#79

[wenzeslaus]

This causes some, but not much changes in r.pops.spread test results:

======================================================================
FAIL: test_outputs_mortality_pesticide_treatment (__main__.TestSpread.test_outputs_mortality_pesticide_treatment)
Check mortality together with pesticide treatment (all_infected_in_cell)
----------------------------------------------------------------------
...
AssertionError: r.univar map=average percentile=90.0 nprocs=1 separator== format=plain -g difference:
mismatch values (key, reference, actual): [('max', 5.6, 5.8), ('mean', 0.526, 0.552422813036034)]
command: r.univar map=average percentile=90.0 nprocs=1 separator== format=plain -g {'map': 'average', 'separator': '=', 'flags': 'g'}

======================================================================
FAIL: test_outputs_mortality_treatment (__main__.TestSpread.test_outputs_mortality_treatment)
Check mortality together with treatment
----------------------------------------------------------------------
...
AssertionError: r.univar map=dead_2020_12_31 percentile=90.0 nprocs=1 separator== format=plain -g difference:
mismatch values (key, reference, actual): [('sum', 2483, 2505)]
command: r.univar map=dead_2020_12_31 percentile=90.0 nprocs=1 separator== format=plain -g {'map': 'dead_2020_12_31', 'separator': '=', 'flags': 'g'}

----------------------------------------------------------------------

[wenzeslaus]

Two tests with mortality in r.pops.spread fail:

def test_outputs_mortality_treatment(self):
    """Check mortality together with treatment"""
# ...
def test_outputs_mortality_pesticide_treatment(self):
    """Check mortality together with pesticide treatment (all_infected_in_cell)"""
# ...

The other two treatment tests without mortality pass even with this change:

def test_sei_treatments_removal_ratio_to_all(self):
    """Check outputs with SEI and treatment_length == 0"""
# ...
def test_sei_treatments_pesticide_ratio_to_all(self):
    """Check outputs with SEI and treatment_length != 0 (pesticide)"""
# ...