add TODO

TODO.md

@@ -0,0 +1,19 @@
+# must have
+
+* View.digest() to emit 'digest' event
+* Views can subscribe to other views' 'digest' events (needed when view resolves
+  expression not from own but from one of the parents' scopes)
+* CollectionView shouldn't introduce additional `<div>` element when it is being
+  parametrized by DOM with just a single element inside
+
+# not likely
+
+* extend show-if, attr- and class- to work as elements, that way they should
+  apply on its parent element so it can be possible to apply directives to
+  View.el
+* more complex expressions
+  * boolean: or, not, and
+  * arithemtics: +, -, /, *
+  * literals: strings, numbers
+  * function calls
+  * ternary expressions; if pred then ... else ...