Avoid deprecation warning

Replace deprecated approxEqual with isClose

Conditional disabled/enabled attributes (#33)

* Add enabled/disabled attributes

* Add enabled/disabled attributes

* Update README.md

* Review comments

* Extract helper function

Co-authored-by: Andre Pany <andre@s-e-a-p.de>
Co-authored-by: linkrope <linkrope@github.com>

Use dshould for fluent assertions

Fix #28: write file and line in hyperlink format

Fix #27

simplified naming

fixed style

made `assertTrue` and `assertFalse` more flexible

support for unit-threaded's fluent assertions