fix #1285: add a check for null host when validating user entered url
code style
rename isValidUrl to isValidUrlAndHostNotNull
Merge pull request #1290 from wordpress-mobile/issue/1285-null-host-setupblog

fix #1285 npe in setupblog
Merge branch 'develop'

Conflicts:
	src/org/wordpress/android/util/UrlUtils.java