Closures: Creating initial test for #20
Updating Closure evaulation handling.
Adding Closure support for boolean, repeat, and omit-tag
Fixing syntax for omit-tag boolean check

instanceof apparently requires an argument that can be an object instance,
but this is not always the case
Closures: updating test for PHP 5.2 compatibility
Closures: updating test for proper use with tal:replace
Closures: adding test to confirm non-closure analogs also work
Closures: Updating check for closure call for data type compatibility
Closures: adding tests for contained and nested closures
Supporting nested closures
Closures: Support for method calls and objects
Closures: updating code for php 5.2 compatibility

`is_a` is deprecated in PHP 5.2, though undeprecated later.
However, it cannot be called in PHP 5.2 as this issues
a warning and also breaks a whole lot of tests.

Alternatively, do not call `is_a` or any of the `Closure`
handling if the version is PHP 5.2

Using `is_object(?) && ? instanceof Closure` will not work
because `? instanceof Closure` is actually a *syntax*
error if `?` is a constant.  This requires avoiding
the call to `? instanceof Closure` altogether, which
requires `is_a`.
Closure handilng: fix bug in comparison

Made the mistake of using float for what should be
a string comparison in PHP versions
Using instanceof over is_a for Closure comparison
Improved/Generalized Closure handling

Code is no longer dependent on php version by using
`instanceof` over `is_a`.

Addition of `phptal_unravel_closure` allows for
consolidation of code that needs to do just that.
Its use incidentally solves the problem of
`constant instanceof` being a parse error.
Merge pull request #21 from ajcrites/tales_closure

Tales closure