Adds 80 chars per line rule in the jshint configuration file.

.jshintrc

@@ -1,15 +1,16 @@
 {
-    "asi": false,
-    "expr": true,
-    "loopfunc": true,
-    "curly": false,
-    "evil": true,
+    "asi": false, // true: Tolerate Automatic Semicolon Insertion (no semicolons)
+    "expr": true, // true: Tolerate `ExpressionStatement` as Programs
+    "loopfunc": true, // true: Tolerate functions being defined in loops
+    "curly": false, // true: Require {} for every new block or scope
+    "evil": true, // true: Tolerate use of `eval` and `new Function()`
     "white": true,
-    "undef": true,
-    "browser": true,
-    "node": true,
+    "undef": true, // true: Require all non-global variables to be declared (prevents global leaks)
+    "browser": true, // Web Browser (window, document, etc)
+    "node": true, // Node.js
     "trailing": true,
-    "indent": 4,
-    "latedef": true,
-    "newcap": true
-}
+    "indent": 4, // {int} Number of spaces to use for indentation
+    "latedef": true, // true: Require variables/functions to be defined before being used
+    "newcap": true, // true: Require capitalization of all constructor functions e.g. `new F()`
+    "maxlen": 80    // {int} Max number of characters per line
+}