tsfy all features example

[qili26]

After pre-canary, only 1 base example was tsfied. This is to just tsfy the all features example so that when we have new codes pushed, we have a demo page for examination.

1. Tsfy all features exmaple.
   1.1 Move DropdownEditor to the demo folder with tsfying.
   1.2 Move Toolbar to the demo folder
   1.3 Move ImageFormatter to the demo folder.
2. Remove immutable examples.
3. Redirect to all features example by default.