Merge pull request #28 from arthuredelstein/web-edit

REPL behavioral features (*e, more err line numbers)
io.cljs: implement classpath-like search for resources.

cljs.io/*clojurescript-home* is set to the top of the Clojurescript
directory.

cljs.io/*classpath-suffixes* represents the list of subdirectories
with *clojurescript-home* that are searched for resources.
Factor out common REPL code to cljs/cljs/repl.cljs

Also get nodecljs.cljs working using repl.cljs and add example
shebang.cljs which can be executed directly.
Features added:
1. *e returns the most recently thrown error in the REPL.
2. If multiple forms are submitted at the REPL, then forms are evaluated in order until
   an error occurs. If an error occurs, the error is printed. Otherwise the value of the
   last form is printed and assigned to *1.
3. Line numbers are shown for all printed errors.
use cljs.core/*e instead of clojure.core/*e
factor out jqconsole code into webconsole.cljs
File editor for web repl:
1. Create a CodeMirror-based file editor (in webedit.cljs)
2. Create webrepl3.cljs and repl3.html, which use the file editor
3. build2.sh builds the console-only version of clojurescript.net;
   build3.sh builds the version including both console and file editor.

The file editor's contents can be evaluated in the REPL by pressing
Ctrl/Cmd+E, and the editor itself can be shown and hidden by pressing
the Show/Hide file editor link.
Merge remote branch 'arthuredelstein/web-edit' into cljs_in_cljs
Merge branch 'cljs_in_cljs' into gh-pages
Rebuild web REPLs.