updates README.md for grammar and table formatting
removes extraneous empty lines and redundant comments; reformats some conditionals
adds data-confirm, data-minlength, and data-maxlength
adds .gitignore
minor update to describedby text in README
updates pattern failure logic and failure description logic

* If pattern fails due to value being empty, don't report pattern failure; let 'required' handle it instead
* Failure messages appended to describedby element rather than stopping after the first failure message.
Merge branch 'bmahoney-updates'