#31 - if build fails due missing dependecies, suggest to run yum-builddep

This is my solution to issue 31. For somebody maybe partial.

When you are missing dependencies it will just write:
```
########## ERROR ############
Error running command: LC_ALL=C rpmbuild --define "_source_filedigest_algorithm md5"  --define "_binary_filedigest_algorithm md5"  --define "_sourcedir /tmp/tito-build/rpmbuild-tito-cf62e449b30c0a07bdcb8c6720c41d5fff73a04eYQkBQ9/SOURCES" --define "_builddir /tmp/tito-build/rpmbuild-tito-cf62e449b30c0a07bdcb8c6720c41d5fff73a04eYQkBQ9/BUILD" --define "_srcrpmdir /tmp/tito-build" --define "_rpmdir /tmp/tito-build"   --clean -ba /tmp/tito-build/rpmbuild-tito-cf62e449b30c0a07bdcb8c6720c41d5fff73a04eYQkBQ9/SOURCES/tito-git-23.cf62e44/tito.spec
Status code: 256
Command output: error: Failed build dependencies:
        asciidoc is needed by tito-0.4.11-1.git.23.cf62e44.fc18.noarch

ERROR: Please run 'yum-builddep tito.spec' as root.
```
I'm not fun of idea to automatically install it. This is enough for me. So if somebody want to install it, then I will leave rest of the work for somebody else :)