Change the default units to their dimensional version (#82)

the units exported at the top level of tunits didn't have the dimension
information because of backwards compatibility ... this PR changes that

part of b/411725412

Author: NoureldinYosri

test/cirq_compatibility.py

@@ -22,7 +22,7 @@ def test_to_json() -> None:
     assert (
         cirq.to_json(tu.ns * 3)
         == """{
-  "cirq_type": "tunits.Value",
+  "cirq_type": "tunits.Time",
   "value": 3,
   "unit": "ns"
 }"""
@@ -31,7 +31,7 @@ def test_to_json() -> None:
     assert (
         cirq.to_json(tu.GHz * [1, 2, 3, -1])
         == """{
-  "cirq_type": "tunits.ValueArray",
+  "cirq_type": "tunits.FrequencyArray",
   "value": [
     1.0,
     2.0,

test/test_value.py

@@ -283,9 +283,9 @@ def test_format() -> None:
     assert f'{x:0.2f}' == '0.42 ns'
     assert f'{x:e}' == '4.234324e-01 ns'
 
-    x = 42.235 * tu.GHz
-    assert f'{x:0.2f}' == '42.23 GHz'
-    assert f'{x:0.1e}' == '4.2e+01 GHz'
+    y = 42.235 * tu.GHz
+    assert f'{y:0.2f}' == '42.23 GHz'
+    assert f'{y:0.1e}' == '4.2e+01 GHz'
 
     assert f'{tu.GHz}' == 'GHz'
     assert f'{2*tu.GHz}' == '2 GHz'

tunits/__init__.py

@@ -98,4 +98,4 @@
 from tunits import units as units
 from tunits import units_with_dimension as units_with_dimension
 
-from tunits.units import *
+from tunits.units_with_dimension import *