[Feature] Add support for UnaryMinus and UnaryPlus expressions

[marcovtwout]

Fixes #140

[scrutinizer-notifier]

The inspection completed: No new issues

[lisachenko]

Hello, nice PR! Could you please also add a test somewhere for this, so it will be tested as well?

[marcovtwout]

@lisachenko I implemented these in a similar fashion as the other resolveExpr functions in that class such as resolveExprBooleanNot(), but didn't find any tests for those in the test suite. I tested them manually, but if you have a suggestion on how to test these I'll write some tests.

[marcovtwout]

@lisachenko Since there are no tests yet for the other features and this is still for the dev-version, perhaps merge this and create a seperate issue for adding tests?

[A-jay98]

@lisachenko Could you give an update regarding this issue? It would be great if you could merge this so that the current version of the library becomes useable again.

[lisachenko]

thx @marcovtwout 👍