Textarea with linefeeds - Fixes #1068

[twalpole]

This makes the behavior of textareas with linefeeds in RackTest more like the behavior with Selenium - Fix for issue #1068

[twalpole]

@jnicklas I moved the modify textarea contents part of this into one place Capybara::HTML - If there's a different place you think it would fit better (or different name) let me know and I'll make that change

[jnicklas]

It almost sounds like this should be fixed upstream in Nokogiri?

[twalpole]

I think there is a good argument to be made that the textarea parsing portion of this is a bug in Nokogiri or more exactly libxml2 when parsing html. However since we already had a partial fix for this in capybara (which "breaks" submission in some cases) it might be worth making the fix correct and then seeing if we can get it fixed upstream. The cr/lf portion of this affecting submission is not an issue in nokogiri - its just mimicking the behavior of full browsers

[twalpole]

@jnicklas the requirement for ignoring leading line breaks comes from http://www.w3.org/TR/html401/appendix/notes.html#notes-line-breaks - This specifically refers to rendering, and browsers have taken this to affect the value - I think this makes the case that its an issue in parsing in Nokogiri/libxml2 less clear