Fixed Basic Wrapper bug

alexInputPrevChar was short one value in the tuple which cause
an error when using left_ctx.  This patch adds the missing `_`
and includes a type signature which will prevent this bug in
the future.
Merge pull request #20 from antarestrader/patch-1

Fixed Basic Wrapper bug
add a test for #20, #15
Merge branch 'master' of github.com:simonmar/alex

* 'master' of github.com:simonmar/alex:
  Fixed Basic Wrapper bug
bump to 3.0.5
alex.cabal: the test suite requires 'base' as a build input
Merge pull request #21 from peti/master

Fix build of the test suite