'here' is deprecated, long live 'context'

'here' has been deprecated for use in page templates (has been for some time) 'context' should always be used in it's stead. 'here' no longer works in some cases and also it makes more sense to use 'context' as this is in use in python files for the same purpose.

e.g.

      <h1 tal:content="here/Title">
	Title
      </h1>

should be:

      <h1 tal:content="context/Title">
	Title
      </h1>

BUT

to get the current url still use 'here_url'; there is no 'context_url'.

e.g.

<b tal:content="here_url" /> - works <b tal:content="context_url" /> - does not work