Add support for :apropos from Idris compiler
Add idris-apropos to the menu
Support IDESlave text formatting instructions in docstrings
Add a note about fonts and colors to the readme

There are instructions for changing them. Fixes #92.
Merge pull request #99 from david-christiansen/readme-colors

Add a note about fonts and colors to the readme
Merge pull request #98 from david-christiansen/text-formatting

Text formatting
Describe formatting in docs
Added note about overlapping
Merge pull request #100 from david-christiansen/docs

Describe formatting in docs
Add support for keywords in REPL output

This relies on https://github.com/idris-lang/Idris-dev/pull/985 getting merged.
Add keyword highlighting to docs
Add menus for interpreter options

Now, settings in the running interpreter can be modified using
menus. Thus far, only showing implicits and error context are supported,
but the system is straightforward to generalize.

This is not done using customize because the typical use case is to
briefly toggle them while debugging, and persistency is not desired.
Merge pull request #102 from david-christiansen/options-menus

Add menus for interpreter options