Small tweaks to whitespace indentation.

Reason: match copy and pasting from the written code lab.
Fix for "Cannot read property 'todos' of undefined" error

storage[this._dbName] is not initialized the first time the app is installed.

To reproduce, make sure local app data is deleted completely and relaunch the app.

On Mac:
1) Shut down Chrome completely
2) Delete /Users/[USER NAME]/Library/Application Support/Google/Chrome/[Default or Profile]/[app id]
3) Empty Mac Trash to make sure it's completely gone
4) Relaunch TodoMVC app
Indentation/whitespace adjustment
Fix for "Cannot read property 'todos' of undefined" error (across ALL codelab steps)
Small whitespace and text changes after going through Step 4 of Codelab.
Whitespace adjustments after going through step 5
Missing ending semicolon.