1. Add ale.setup and ale.setup.buffer for pure Lua configuration.
2. Update many global settings to use Booleans instead of numbers to
make types easiert to work with in Lua.
3. Radically reformat documentation and fix errors to make
documentation more usable for Neovim users.
* Detect and use CM files for smlnj
* Split into two checkers
- one for CM projects
- one for single SML files
* Fix some typos
* Fix error caught by writing tests
We want to actually use `glob` to search in paths upwards from us.
(Previously we were just searching in the current directory every time!)
* Fix errors from former test run
* Write tests for GetCmFile and GetExecutableSmlnj
* Typo in 'smlnj/' fixture filenames