Add `==` and `!=` to compare arrays
Remove .NaN equality check
Improve array equality check
Add `==` and `!=` to compare dictionaries
Add subscript setters
Add boolean literal conversion
Add integer literal conversion
Add float literal conversion
Add unary `-` operator
Add string literal conversion
Add array literal conversion
Add dictionary literal conversion
Remove redundant `==` and `!=` operators

After adding literal conversions, these operators are not useful anymore
since conversion is applied automatically.