Always treat \r and \n as newlines

[smashwilson]

By configuring pcre to recognize any unicode newline sequence, we can prevent . from matching \r on files with \r\n newlines. This makes superstring's regex matching more consistent with JavaScript's and avoids problems like atom/atom#17023, where a scanInRange() callback is triggered with a null match.

[smashwilson]

@maxbrunsfeld I just noticed that you'd done this (better) before in dc40bb9, but reverted it in 8ff2830 with a note that #define NEWLINE_DEFAULT 2 matched JavaScript better. Do you remember in what context it did? Was it in the way ^ and $ were handled, or multiline mode?

I know that . does not match \r in JavaScript:

> /./.exec('\r')
null

But pcre did before this change.