Update snippets according to the Crockford's code conventions

This removes unneeded semicolons, makes JSHint/JSLint not generate warnings, improves readability. The snippet for the anonymous function is now easier to use as a callback, because of no need to remove the semicolon every time.

More info: http://javascript.crockford.com/code.html
Update indentation rules for the switch statement

To match the Crockford's code conventions ( http://javascript.crockford.com/code.html ), improving readability.
Convert get snippet into four snippets all set to get⇥

The previous snippet required further input to select the type, by using four snippets with the same trigger we get a menu to select the desired type.
Add new snippets: do, else, for in, setInterval, switch, try, while
Remove redundant snippets

"Object Value JS" literally duplicates the 'Object key — key: "value"' snippet.
"Object Method String" provides the code the I highly doubt that many people will use if any.
Remove trailing return from prototype snippet