Signal Desktop: v1.2.0 Release

Note: This release is equivalent to v1.2.0-beta.2. Listed below are the changes from the previous production release: v1.1.0

Update to Electron 1.7.10 (#1919)

Fixed: clicking Windows notification breaks window out of aero-snap location (#1918)

Fixed: forwarded video would not play (#1977)

Fixed: conversation was inaccessible if group member had invalid phone number (#1968)

Fixed: powershell warning caused cert validation of downloaded update to fail on windows (#1976)

Fixed: 'Missing signed prekey' errors after re-link (#1979)

Fixed: data older than three days would persist in logs dir (#1945)

Fixed: in the middle of send, disabled send field could be edited after click (#1937)

Update strings (#1921)

Add badge with unread count to the tray icon - thanks @m-pilia (#1934) Note: to try this test feature out, use the --use-tray-icon and --start-in-tray command-line arguments

Dev: - Additional logging for unexpected situations during sort of conversation list (#1969) - Log more info along with http errors (#1968) - Fix error to console when verifying contact in standalone mode (#1961) - Remove all built assets from repo (#1955) - Log out information from DOMException when import fails (#1923) - Log clearer messages regarding prekey/signed prekey fetches (#1961) - Make errors more debuggable; capture correct stack, include name (#1944) - Add eslint/mocha with code coverage for non-browser code (#1945) - Revamped github issue and pull request templates, updates to contributing.md/readme.md (#1955 and #1956) - Document building/testing releases in Contributing.md, thanks @veggiedefender (#1867) - Dependency updates, fixes required for successful release (#1966 and #1976) - Update a number of dependencies to the latest: builder, websocket, spellcheck (#1920)