add depends command

Currently it lists all BRs of a hackage
though this may change to just Haskell depends
rename trySystem to runSystem and add new trySystem to allow yumInstall to fail

So yumInstall can now fail for "cblrpm install" for non-packaged deps
but still not "cblrpm rpm".
bump to 0.8.8, more description, and new todos
document new depends command