Added encoding of tab symbol to encodeStepString() method.

[UsoltsevaM]

Tab symbol was not encoded in encodeStepString() method which led to illegal character error while IFC schema check.
This pull request adds encoding of tab symbol.

[ifcquery]

I can not merge anything at the moment, because it messes up the licenses.
If you agree, I can add this code snippet to the main branch and check it in from my repository?

[UsoltsevaM]

I can not merge anything at the moment, because it messes up the licenses. If you agree, I can add this code snippet to the main branch and check it in from my repository?

Yes, please.

[UsoltsevaM]

I can not merge anything at the moment, because it messes up the licenses. If you agree, I can add this code snippet to the main branch and check it in from my repository?

Could you please clarify what "messes up the licenses" means? Is it a temporary problem? Does it mean anything for the users?