Add `pattern` to document about binding property

`Ember.TextField` supports `pattern` as its binding property.
Merge pull request #2290 from tricknotes/fix-doc

Add `pattern` to document about binding property
Fix document indent
Merge pull request #2291 from tricknotes/fix-document-indent

Fix document indent
Use `function.call` instead of `function.apply`

The former is faster than latter in a lot of cases.
Remove unused variable
Merge pull request #2292 from tricknotes/use-call-instead-of-apply

Use `function.call` instead of `function.apply`
Merge pull request #2293 from tricknotes/remove-unused

Remove unused variable