refactor($compile): move function def out of loop
fix($compile): accessing controllers of transcluded directives from children

Additional API (backwards compatible)
- Injects `$transclude` (see directive controllers) as 5th argument to directive link functions.
- `$transclude` takes an optional scope as first parameter that overrides the
  bound scope.

Deprecations:
- `transclude` parameter of directive compile functions (use the new parameter for link functions instead).

Refactorings:
- Don't use comment node to temporarily store controllers
- `ngIf`, `ngRepeat`, ... now all use `$transclude`

Closes #4935.
fix(ngAnimate): use a fallback CSS property that doesn't break existing styles

The clip property seems to remove the box-shadow property when an absolute
positioned animation is ongoing. This fix changes the property to be border-spacing
which is also very underused. The border-spacing CSS property is only visible
when border-collapse is set to separate.