First you have some globally accessible array of key->value pairs which contain the data to be entered into templates

	Then you have some template files

tem_set($key, $value)
tem_get($key)
tem_run($file/template)
tem_echo($file/template) { echo tem_run($file); }

This should work for simple templates such as:  foo: '~foo~'


	It gets trickier when you have bits in your template that need to be repeated
	(with different tags each time) and others perhaps not displayed at all.

	foobar.html:

<table>
<tr><th>foo</th><th>bar</th></tr>
<!--~foobar_row start~--><tr><td>~foo~</td><td><input value="~bar~"></tr><!--~end~-->
</table>

tem_load('foobar.html');

		
		the main template (with the sub-templates like foobar_row replaced with a single tag ie:

<table>
<tr><th>foo</th><th>bar</th></tr>
~foobar_row~
</table>

	Main data structure:
		key/value pairs
		template file (if template string is empty, it will be read from here)
		template string
		sub templates:
			key: foobar_row
			value: <tr><td>~foo.....html~</td><td><input value="~bar.attr~"></tr>


tmpl_insert('foobar_row');