Make the scheme of the URI optionally optional
Rename require_scheme to scheme_required, and update validation to not include the deprecated FILTER_FLAG_HOST_REQUIRED and FILTER_FLAG_SCHEME_REQUIRED constants. Also, show a special error message if the scheme is missing.
start better validation
Switch to regexp from dperini
The PHP filter function validates completely invalid URIs such as "http://http://". This regexp is very reliable. See regexp comparisons here: http://mathiasbynens.be/demo/url-regex
3 fixes:
"." at the end of the error message
remove "://" from the scheme
remove unused var
remove ws
explicitly match preg_match value
line breaks
Small cleanups to regex.

 * use extended syntax
 * clean up docs
 * remove non-capturing subpatterns
 * wrap some lines better
Merge branch 'nburka-uri-entry-scheme-optional' of github.com:gauthierm/swat into gauthierm-nburka-uri-entry-scheme-optional

Conflicts:
	Swat/SwatUriEntry.php
somehow this var came back after merging mike's change
let's get explicit
Merge pull request #4 from nburka/uri-entry-scheme-optional

Make the scheme of the URI optionally optional