Bug 855765 - Move test_bug_795164 to dom/apps and avoid UI confirmation. r=fabrice

--HG--
rename : dom/apps/tests/test_uninstall_errors.html => dom/apps/tests/test_bug_795164.html
Bug 920092 - ensure printing human readable error message on app install error. r=paul
Bug 920337 - Use promise to ensure we don't miss project load. r=paul
Bug 875731 - Replace callers of nsIDownloadManager.usersDownloadsDirectory with Downloads.getUserDownloadsDirectory in browser/metro/. r=mbrubeck
Bug 875731 - Replace callers of nsIDownloadManager.usersDownloadsDirectory with Downloads.getUserDownloadsDirectory in browser/devtools/. r=jwalker
Bug 918354 - Remove outer try/catch in osfile_async_worker.js. r=yoric
Bug 919506 - Fix browser.bookmarks.autoExportHTML not working due to bug 910885. r=mak