Fix alerts component/containers and CSS styling

Removing highlight when hovering over alert close button after one closes, other minor styling fixes.

Use defineMessages to allow messages to be found by the automatic extraction tool.

chore(package): update scratch-vm to version 0.2.0-prerelease.2018100…

Update text-encoding to the latest version 

Closes #3245

and other small sprite and costume library updates

welcome modal doesn't appear when a project is loaded directly

Deploy Smoke to Master

Made border color of stage selector be same as other border colors

Deploy to Smoke Branch

Add onShare prop to enable the share button

Don't show the "Give Feedback" button if there is a session

log workspace update errors

* Add mic indicator

* Fix mic indicator position and margin

* Don’t always show indicator, don’t sneaky-enable extension

* Position mic indicator in RTL

* Actually, don’t move indicator in RTL

* Update event name for MIC_LISTENING

* Move mic indicator state into redux

* Move stageSizeToTransform into screen-utils

* Position mic indicator and question at bottom of stage

* Fix pointer events

* JSDOC for stageSizeToTransform

* Pass micIndicator into StageComponent via …props

Update scratch-l10n to the latest version 

chore(package): update scratch-blocks to version 0.1.0-prerelease.153…

Update react-modal to the latest version 

Expose AppStateHOC component

Update react-popover to the latest version 

Closes #3222