Added Angle unit with Degrees, Radians and Gradians.
Merge remote-tracking branch 'gpetrou/Angles'
Added missing reference to Angle.cs in Src/UnitsNet/UnitsNet.netcore45.csproj.
Removed space between value and degree char in Angle.ToString().
Added test case in AngleUnitsRoundTrip() for degrees.
Added comments to ignore ReSharper warnings.
Added TryConvert case for Angle in UnitValueTests.cs.
Added comments to disable ReSharper warnings in tests.
Added test cases for Angle in UnitConverterTests.cs
* TryConvertReturnsFalseOnIncompatibleUnits()
* ThrowsOnIncompatibleUnits()
Added TryConvertReturnsTrueOnCompatibleUnits() to Tests/UnitConverterTests.cs.
Added missing test case for volume in Tests/UnitConverterTests.cs and TryConvertReturnsFalseOnIncompatibleUnits().
Added missing tests for Convert() and TryConvert() for area, volume and force units in UnitConverterTests.cs.
Added missing case in DegreesToAngleUnits() in AngleTest.cs.
Added test case DegreesToAngleUnits() in Tests/UnitConverterTests.cs.
Code cleanup in Tests/UnitConverterTests.cs.
Fixed bug in UnitConverter.TryConvert() of pressure units to NewtonPerSquareMillimeter and NewtonPerSquareMeter.
Minor code cleanup in Tests/PressureTests.cs.
Added missing test for Force units in UnitValueTests.cs.
Added test cases for force and pressure units in Tests/UnitConverterTests.cs.
This helped discover a bug in UnitConverter.cs for dynamic pressure conversions.
Fixed a bad test case in AngleTest.cs for DegreesToAngleUnits().