templater: add context.preload(t) to test if the specified template exists
I'm going to remove 'templ' from the resources dict because it is the only
resource that the caller can't provide. This also implies that putting
'templ' into the resources dict creates a reference cycle.
context.preload(t) will be used in place of templater.__contains__().
{
// Enforcing
"eqeqeq" : true, // true: Require triple equals (===) for comparison
"forin" : true, // true: Require filtering for..in loops with obj.hasOwnProperty()
"freeze" : true, // true: prohibits overwriting prototypes of native objects such as Array, Date etc.
"nonbsp" : true, // true: Prohibit "non-breaking whitespace" characters.
"undef" : true, // true: Require all non-global variables to be declared (prevents global leaks)
// Environments
"browser" : true // Web Browser (window, document, etc)
}