Included documentation browser UI template.

The source comes from official ExtJS documentation (included in
ExtJS release package).  This includes the minified version of
ExtJS 3.3.1 with gray style.

The original ext-3.3.1/docs/resouces contained a lot of unused
CSS and image files - these were all excluded as unnecessary crap.

JsDuck now includes --template command-line-option to specify
alternate template to use.  By default the template/ dir included
with jsduck will be used.