Added HTML5 webapp manifest

Added W3C webapp manifest file. N.B. the file is prefixed "web-" to prevent conflict with Chrome manifests

Updated shortname based on feedback

Fixes #495

Rename web-manifest.json to manifest.json
bump deps
Merge pull request #544 from paddy2k/master

Add W3C Webapp Manifest
Merge pull request #539 from stevemao/patch-1

Bump dependencies (imagemin, replace, flatten)
Merge remote-tracking branch 'upstream/master' into beebo