suppress many analyzer warnings

the ones that remain are all legitimate issues that need to be
addressed, I believe
suppress warnings in windows.dart

missed this file in my previous commit
Merge pull request #82 from rmsmith/warning_suppression

Warning suppression
adding the chrome.syncFileSystem api
use chromeProxy in file_system.dart and sync_file_system.dart
Merge pull request #84 from dart-gde/new-apis

adding the chrome.syncFileSystem api
Adding media galleries interface
Merge pull request #66 from financeCoding/media_galleries_interface

Adding media galleries interface