Use absolute paths when passing install dirs to the setup script.

Before: '--libsubdir=$arch-$os-$compiler/$pkgid'.
After:  '--libsubdir=i386-linux-ghc-7.4.2/lifted-base-0.2.1.0'.
Distribution/Client/Tar.hs: make clearer error message when tar fails to unpack source

Patch improves error reporting to give a clue what broke
when unpacking:
    $ dist/build/cabal/cabal unpack hackport
    Unpacking to hackport-0.3.2/
    cabal: File in tar archive is not in the expected directory "hackport-0.3.2"
    but got the following hierarchy: [".",".","@LongLink"]

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Merge pull request #1395 from trofi/master

Distribution/Client/Tar.hs: make clearer error message when tar fails to...
Tweak an error message.
Typo.
Merge remote-tracking branch 'upstream/master'
implemented "back" does not play nicely with bookmarks yet
nicer "back"