Feature request: Equivalence of expressions

[pamelafox]

A few equivalence understandings would help grading a lot:

• it should treat “$b + $a” the same as “$a + $b” for binary operators that we specify
• it should treat “$a += $b;” the same as “$a = $a + $b” for binary operators
• It should treat $a++ the same as $a += 1
• It should treat $a <= $b the same as $b >= $a
• It should treat $a < $b the same as $b > $a
• it should treat “var $a= $x;” the same as “var $a; $a=$x”

[pamelafox]

I believe @mr-martian's change addresses two of these equivalence needs.

Here are a few more:
$a <= $b is same as $b >= $a
$a < $b is same as $b > $a