improving readability and performance

small refactoring by @dhh suggestion
comments by @reed
Merge pull request #231 from keram-refinery/refactoring

improving readability and performance
Update README.md
Merge pull request #238 from kathryneh/patch-1

Fix typo
Update README.md to fix overflowing code snippet

The "Asset change detection" code snippet overflowed from the 
content area, so I added a newline in the middle of it and made
it be a code block.
Merge pull request #240 from VesQ/patch-1

Update README.md to fix overflowing code snippet
Add link to Flask Turbolinks
Record changes from PR 231
Add the page:before-change event