Updated installation instructions.

Added note on checking that `~/.cabal/bin` was added to `$PATH`.
Merge pull request #9 from jfdm/cabal-problems

Updated installation instructions.
Updates for 0.9.11
Merge branch 'master' of github.com:idris-hackers/idris-tutorial

Conflicts:
	content/interp.tex
Add missing quotation marks in syntax example
Merge pull request #12 from JanBessai/master

Add missing quotation marks in syntax example