Refactor code-style

* Remove superfluous files; * Remove unneeded Node targets from Travis; * Replace `istanbul` with `nyc`; * Replace `eslint`, `jscs` with `xo`.

Author: wooorm

.editorconfig

@@ -2,14 +2,8 @@ root = true
 
 [*]
 indent_style = space
-indent_size = 4
+indent_size = 2
 end_of_line = lf
 charset = utf-8
 trim_trailing_whitespace = true
 insert_final_newline = true
-
-[*.{json,remarkrc,eslintrc,sh}]
-indent_size = 2
-
-[*.md]
-trim_trailing_whitespace = false

.eslintignore

@@ -1,5 +1,6 @@
 .DS_Store
 *.log
+.nyc_output/
 coverage/
 node_modules/
 mdast-util-to-nlcst.js

.eslintrc

@@ -1,12 +1,9 @@
 language: node_js
 node_js:
 - '0.11'
-- '0.12'
-- '4.0'
 - '5.0'
 - '6.0'
-sudo: false
-after_success:
+after_script:
 - bash <(curl -s https://codecov.io/bash)
 deploy:
  - provider: npm