add support for building by Tito

This is my reaction to part of Makefile in PR #15.  You can try this:

You can all this try - none of this step will do "git push" so it is safe to experiment"
```
dnf install tito
# bump up version, create changelog (second tagging will suggest changelog from commits)
# and create git-tag
tito tag
# in real life you will do git push as told, but for testing just skip it

# do package from last tagged commit. These commands check if the tag exist in remote repo
#(so you are not making package from stuff other do not see). But since you did not git-push,
# just add --offline
tito build --srpm --offline
tito build --tgz --offline
tito build --rpm --offline
# build from last commit
tito build --rpm --test --offline
# notice that is automaticaly changed dist tag, so it is obvious that it is not released package
# clean up, undo last tag
tito tag -u
```
And as benefit you can easily import package into Fedora dist-git (this will do git push to dist-git!):
```
tito release fedora-master-git
```