fix rpmbuild arglist; improve yumInstall soft behaviour
rename runCmd to cmd_ and tryReadProcess to cmd; rpmBuild_; yum localinstall

like in fedora-haskell-tools:Utils (cmd removes trailing newline)
- add sudo
- rpmBuild now returns spec filename for install rpmspec
findPkgName and findSpecFile to use right specfile

this extends the improve specfile handling from Spec
to RpmBuild and Diff and now Install.

Basic recursive building with "cblrpm install" now works.