add fixpoint type to handle conditions

[christian-lanius]

This pull request fixes issue #42
However it misses a test for this. The previously failing excerpt from my sdf file can be found in the issue. I am unsure how to write set up a proper test for this. Doing it the "simple" way results in a comparison between two equivalent files, which have different white space however.

[mithro]

Hi,

Thank you for sending the pull request! It's awesome to see you contributing to this project. However, before I can look at this request you need to add DCO sign-off to commits in this repository.

We require DCO sign-off for all commits to this repository (including all authors). Please see the following URL to see more information and BeeWare also have a Beginners guide to DCOs.

You can use git commit --amend --signoff and then a git push --force to add the signoff. You can also use git rebase --signoff.

Thanks!

[christian-lanius]

I did the DCO sign-off as requested and I also added a test case, which fails in the current master branch.

[mithro]

@kgugala - Could you please review (or assign someone to review)?

[kgugala]

@christian-lanius thanks for the PR. Generally looks good. Please see my comments

[kgugala]

LGTM. Thanks @christian-lanius