Check conversion of string to float on macOS

[scheibel]

The test case fails on macOS (https://travis-ci.org/cginternals/cppassist/jobs/195219351)

[Tobias1595]

Test fixed by 3d5819c (https://travis-ci.org/cginternals/cppassist/builds/228798060)

[scheibel]

This is oddly unsatisfying to see gcc and clang passed the tests with the additional f as float suffix and now they pass without. Do you have any explanation?

[cgcostume]

can this be closed?