Support semantic highlighting of proof state

This isn't the Right Way, which would be to send all the structural
information, but it's straightforwardly achievable right now and an
improvement on what's there.
Merge pull request #208 from david-christiansen/keydef-file

Support semantic highlighting of proof state
Remove idle timers

It seems that idle timers are causing all kinds of problems, so rather
than deal with that complexity, the clickable module feature has been
moved to an after-save-hook.

RE #206
Merge pull request #209 from david-christiansen/timer-removal

Remove idle timers
Compute command line arguments for package member
Add a hook for literate Idris files

This can be used to set up e.g. extra highlighting of the text portions.
Merge pull request #210 from david-christiansen/lidr-hook

Hook for .lidr files + extra ipkg field processing
Add optional help text in metavar list and prover

When idris-show-help-text is non-nil, helpful descriptions are shown in
the prover and metavariables.
Merge pull request #211 from david-christiansen/help-text

Add optional help text in metavar list and prover