haskell-idris: revert update to version 0.9.9

This reverts commit 61c880d5582c9bfd91a4ddb9c27973e31aed8c12. The new
Idris version depends on a version of LLVM that we don't have in master
yet: it's only in x-updates.
bison3: mark low-prio until the check phase is fixed
lightdm updates (merge #574)

Also fixes the situation where some session stuff is written to nix store.
haskell-git-annex: update to version 4.20130802
haskell-MissingH: update to version 1.2.0.1

Don't run the check phase to avoid depending on the obsolete testpack package.
haskell-numeric-prelude: update to version 0.4.0.3
haskell-shakespeare: update to version 1.0.5.1
haskell-stylish-haskell: update to version 0.5.7.0