change FloatRange arguments minval/maxval to min/max

in the previous version FloatRange(max=100) was neither working
properly nor complaining, because the maxval=None default was
overriding the value for max.

possible fixes:
  - raise an error when min/max used as argument (confusing for
    the programmer, as it is a property)
  - allow both versions minval/maxval and min/max (more code)
  - use min/max and a pylint directive here (the only thing to
    take care is not to use the min/max builtin in __init__)

this change uses the last option for the fix

Change-Id: Iff0e0c4d0d7b165003bdeffa67a93a1cd7f29eea
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/31982
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

test/test_datatypes.py

@@ -160,9 +160,9 @@ def test_ScaledInteger():
     with pytest.raises(ProgrammingError):
         ScaledInteger('xc', 'Yx')
     with pytest.raises(ProgrammingError):
-        ScaledInteger(scale=0, minval=1, maxval=2)
+        ScaledInteger(scale=0, min=1, max=2)
     with pytest.raises(ProgrammingError):
-        ScaledInteger(scale=-10, minval=1, maxval=2)
+        ScaledInteger(scale=-10, min=1, max=2)
     # check that unit can be changed
     dt.setProperty('unit', 'A')
     assert dt.export_datatype() == {'type': 'scaled', 'scale':0.01, 'min':-300, 'max':300,
@@ -563,7 +563,7 @@ def test_get_datatype():
     assert isinstance(get_datatype(
          {'type': 'scaled', 'scale':0.03, 'min':-99, 'max':111}), ScaledInteger)
 
-    dt = ScaledInteger(scale=0.03, minval=0, maxval=9.9)
+    dt = ScaledInteger(scale=0.03, min=0, max=9.9)
     assert dt.export_datatype() == {'type': 'scaled', 'max':330, 'min':0, 'scale':0.03}
     assert get_datatype(dt.export_datatype()).export_datatype() == dt.export_datatype()