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.
* ale.txt: fix indentation
* ale.txt: fix Type and Default markup
* ale.txt: use `not set` instead of `undefined`
This matches the way the variables are referenced in prose about
existence state.
* Add kotlin languageserver linter definition
* Added kotlin languageserver references in docs, fix missing !! on other linters
* Added Vader tests for root path detection in Kotlin Language Server
* Add ktlint support (without formatting) for kotlin filetype
* Fix code style and refactor to use ALE utility functions (GetMatches)
* Remove options for configuration file
* Refactor: Rename exec variable and use ale#Set for variable configuration
