Remove Short delimers

[dymk]

It does not seem they fill a useful role; 99% of all Temple templates I've seen in the wild only use <% %> and <%= %> delimiters.

The temple parsing code is also made overly complex due to supporting Short delimers.

If anyone has been using Short delimers, and finds them useful, let me know, and I'll add them back in, but in the meantime, I'll remove this feature.

[DarkRiDDeR]

I use short delimiters sometimes, but I don't see a problems to start using only <% %> and <%= %> delimiters. I support this decision if it greatly simplifies the parsing