introduce Urls.newUri, prepare to fix WEB-9968 Dart: ClassCastException when debugging web application in Dartium
(cherry picked from commit 4ecac7f)
NetUtils.tryToFindAvailableSocketPort
(cherry picked from commit fa39c70)
newHttpUrl — authority must be NotNull
(cherry picked from commit a708a6e)
continue WEB-9968 Dart: ClassCastException when debugging web application in Dartium
(cherry picked from commit c19e163)
IDEA-111388 Built-in server not "available external" — it is unclear that port number must be also changed
(cherry picked from commit 6ccdae5)
NPE in mouse handler
IDEA-117059 (error reporting in updater fixed)

- setting/reading hasError flag sequenced properly
- closing ops on ZIP stream moved out of finally blocks so that informative IOExceptions would not get suppressed by cryptic induced ZipExceptions
IDEA-115412 Diff window is minimized  after the appearance
(cherry picked from commit b2307d0)