NixOS fixes

ghc-parser: add missing build-tools directive

Workaround changed API in Chart-cairo 1.3

Various updates

Fix ghc-parser on GHC 7.8.3

In GHC 7.8.3, GHC's parser changed a bit, causing ghc-parser to fail to
build.  I fixed it by following the instructions on issue #268.

allow ipython version 3

GHC 7.8: Fix sandbox support  and some debugging conveniences

As it turns out, setSessionDynFlags calls initPackage. Unfortunately,
initPackage only reads the package database the first time it is called.
Therefore, we need to set extraPkgConfs before we call
setSessionDynFlags for the first time in order for the sandbox to be
used. Since initGhci is the first caller of setSessionDynFlags, we make
it responsible for this.

This confuses distributions which don't use bash as sh

Minor typo fix when installing IPython.