Add build script

To build, run bin/build - it will concat the relevant files and byte-compile

bin/build

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+git status 2> /dev/null 1> /dev/null || (echo "Not in git repository" && exit 0)
+cd $(git rev-parse --show-toplevel) || (echo "Can't find root directory" && exit 0)
+cat lib/js3-head.el lib/js3-externs.el lib/js3-vars.el lib/js3-util.el lib/js3-scan.el lib/js3-messages.el lib/js3-ast.el lib/js3-highlight.el lib/js3-browse.el lib/js3-parse.el lib/js3-indent.el lib/js3-foot.el > js3.el
+emacs --batch -f batch-byte-compile js3.el

js3.el

@@ -1,7 +1,7 @@
 ;;; js3.el -- an improved JavaScript editing mode
 ;;;
 
-;;; js3-mode.el --- an improved JavaScript editing mode
+;;; js3-head.el
 
 ;; Author:  Thom Blake (webmaster@thomblake.com)
 ;; Authors of historical versions:
@@ -82,6 +82,9 @@
 
 ;;; Code:
 
+;;; js3-head.el ends here
+;;; js3-externs.el -- external name definitions
+
 (defvar js3-ecma-262-externs
   (mapcar 'symbol-name
           '(Array
@@ -3235,6 +3238,8 @@ the correct number of ARGS must be provided."
          "Yield from closing generator")
 
 (provide 'js3-messages)
+
+;; js3-messages.el ends here
 ;;; js3-ast.el --- JavaScript syntax tree node definitions
 
 ;;; Code:
@@ -9797,6 +9802,7 @@ nil."
       (when (> offset 0) (forward-char offset)))))
 
 ;;; js3-indent.el ends here
+;;; js3-foot.el
 
 (eval-when-compile
   (require 'cl))
@@ -11105,6 +11111,6 @@ it marks the next defun after the ones already marked."
 
 (provide 'js3-mode)
 
-;;; js3-mode.el ends here
+;;; js3-foot.el ends here
 
 ;;; js3.el ends here