Handled case where onLaunched input is not set

According to https://developer.chrome.com/apps/app_runtime#event-onLaunched, the `launchData` is optional.
Fixed the position of the of senderID heading so that it is aligned with the other text onscreen.
Merge branch 'master' into fix-position-of-sender-id-label
Aligned right edge of missing ID notice with right edge of recipient list.
Let missing ID notice overflow content be visible so that the (!) icon appears onscreen.
Eliminate the possibility of clicking the "Add me as a recipient" link when the missing ID notice is hidden.
Remove x-ray goggles.
Set missing ID notice in the same color as other text onscreen.
Snipped duplicate 'as a recipient' words from first sentence of missing ID notice so that the notice fits on 2 lines instead of one. And adjust icon position to fit.
Position div.nameContainer top at 0px so that really long file names are not truncated awkwardly on the vertical.
Removed phrase that never appears onscreen and also contained a typo.
Let file name extensions wrap to newlines when they won’t fit on one line.
Allow .minilock extensions to wrap onscreen also so that names don’t look weird when they are shelved.
Merge pull request #119 from 45678/let-extensions-wrap-to-fit

Wrap onscreen file extensions to newlines to accommodate some longish file names
Merge pull request #117 from 45678/fix-name-container-top

Better accommodation for really long filenames onscreen
Merge pull request #116 from 45678/fix-missing-id-notice

Fix display of missing ID notice
Merge pull request #118 from 45678/tidy-tidy

Removed phrase that never appears onscreen and also contained a typo
Merge pull request #114 from 45678/fix-position-of-sender-id-label

Position of div.senderID heading
Merge pull request #113 from beaufortfrancois/master

Handled case where onLaunched input is not set
Update background.js