Fix end-of-code-block template token regex

If end-of-code-block template token (`%>`) is followed by a Windows-style newline (`\r\n`), bottle will report `SyntaxError: invalid syntax`. 

Example:
```python
>>> tpl = '<%\r\nprint("hello")\r\n%>\r\nworld'
>>> bottle.template(tpl)
```
Output:
```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "bottle.py", line 3494, in template
    return TEMPLATES[tplid].render(kwargs)
  File "bottle.py", line 3320, in render
    self.execute(stdout, env)
  File "bottle.py", line 3307, in execute
    eval(self.co, env)
  File "bottle.py", line 205, in __get__
    value = obj.__dict__[self.func.__name__] = self.func(obj)
  File "bottle.py", line 3271, in co
    return compile(self.code, self.filename or '<string>', 'exec')
  File "<string>", line 3
    %>
    ^
SyntaxError: invalid syntax
```
Output after fix:
```
hello
'world'
```
Took me a while to catch that bug as it didn't manifest if end-of-code-block is not followed by a newline (i.e. file ends immediately after `'%>'`).