Make LLVM optional but the default
Vector FFI and bitcasts
Cleanup
Add Num and Show instances for the new(ish) arithmetic types
rename fmap to map

To still allow disambiguation of List.map vs. Functor.map on List arguments, I
replaced the former entirely by moving the Functor instance of List into
Prelude/List.idr (and importing Prelude.Functor there).
Uniform vector constructors
Merge pull request #389 from melted/optllvm

Make LLVM optional but the default
Fail idiomatically
Update usage with --codegen and add a couple of other flags.

While we're at it, make it fit in 80 cols.
Implement bitcasts in LLVM codegen
FTy convenience names for fixed-width ints
define and use iputGoal instead of putStrLn
abstract set-prompt into isetPrompt -- and use it
remove duplicate 'intro' and 'intros'
layout improvement
handle Prove in toplevel of ideslave, to reset prompt after it returned
support ideslave mode with prover
more work on the prove mode... now sending messages when it started and finished
send start/end proof mode messages from within prover
cleanups