Plugin Development tutorial code error

Just a small error reported in maillist.
Merge pull request #369 from iurisilvio/patch-1

Plugin Development tutorial code error
Whitespace and typos
Fixed copyright date
Replaced HTTPResponse and HTTPError with subclasses of BaseResponse.
Fix: Bottle no longer changes the Content-Length response header if it was set by the application. (fix #311)
Some micro-optimisations.
Raise RuntimeError when using gevent without monkey-patches.
Removed unused parameter docs from GeventServer
Fixed code indent for one of the examples
Merge pull request #375 from nstawski/master

Fixed code indent in one of the examples
Fix XSS vulnerability in hello world example
use template in tutorial to match index
Merge pull request #376 from graingert/patch-2

use template in tutorial to match index
Avoid __main__.ext namespace

Fix #334.
Merge pull request #378 from iurisilvio/patch-3

Avoid __main__.ext namespace
Fix bottle.ext namespacing when importing as bottle (regression in fix for #334)
Merge pull request #380 from projectgus/master

Fix regression in pull request 378 (issue #334)
plugin.apply: rename context to route
Fix #382 "Test failures with Python 3"
Merge pull request #381 from fredj/plugin-apply-args

plugin.apply: rename context to route