[manifest] Added splashscreens member (closes #9) (#371)

First crack at this... by no means perfect, so comments welcome. 

Doesn't define Android style splash screen processing yet. 

Note I've generalized "processing an array of image objects" to use by both icons and splashscreens. 
You can view, comment on, or merge this pull request online at:

  https://github.com/w3c/manifest/pull/371

-- Commit Summary --

  * Added splashscreens member (closes #9)

-- File Changes --

    M index.html (229)

-- Patch Links --

https://github.com/w3c/manifest/pull/371.patch
https://github.com/w3c/manifest/pull/371.diff

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/manifest/pull/371