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.
* Add prettier fixer support for typescript
* Add prettier fixer support for css and scss
* Add prettier fixer support for json
* Use getbufvar() to get &filetype