Cache template linkers instead of template strings

[kseamon]

Currently, ng:include, ng:view, and directives with templates cache their template strings for future use.

It would probably be better if they instead compiled the template string once then cached the resulting linker.

(just an idea - no hurry)

[IgorMinar]

We should explore this in the future. The idea was on the table when I was
writing this code, but there was a concern about increased memory usage so
we decided to punt on it for now.

[jimmywarting]

another thing that comes to mind is when http interceptor change the response dynamically
and that might be an reson not to cache the compiled template

response: function(res){
   res.data.replace("<now />", '<time datetime="'+ (new Date).toJSON() +'">Today</time>');
   return res;
}

But perhaps caching the compiled template is a good thing for a example ng:repeater?

[IgorMinar]

we will do this and more in v2 but I don't see us changing the current behavior in v1.