Added eslint and editorconfig configs.

Author: victor73

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+max_line_length = 80
+
+[docs/CHANGES.txt]
+indent_style = space
+indent_size = 2

.eslintignore

@@ -0,0 +1,5 @@
+*.md
+LICENSE
+package.json
+package-lock.json
+/docs/**

.eslintrc.json

@@ -0,0 +1,30 @@
+{
+    "env": {
+        "browser": false,
+        "mocha": true,
+        "node": true,
+        "es6": true
+    },
+    "extends": "eslint:recommended",
+    "rules": {
+        "no-console": 0,
+        "no-unused-vars": 0,
+        "indent": [
+            "error",
+            4,
+            {"SwitchCase": 1}
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            2, "single", "avoid-escape"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ],
+        "space-before-function-paren": ["error", "never"]
+    }
+}