Fixes #128

In the interests of non-collision and multiple users, favorites files are now downloaded to a path that includes the user's b32username as well as the full path to the item (storage or share).

Previously:

`https://web-dc2.spideroak.com/storage/MGSXXZ6FMVVXY/DeviceName/Users/tommy/Pictures/best-pic-evar.png`

Would have been downloaded to:

`Download/SpiderOak/.favorites/DeviceName/Users/tommy/Pictures/best-pic-evar.png`

After this change, it would be downloaded to:

`Download/SpiderOak/.favorites/MGSXXZ6FMVVXY/storage/MGSXXZ6FMVVXY /DeviceName/Users/tommy/Pictures/best-pic-evar.png`
Fixes #160 - missing nexus7 icons

Seems that 4.2.x doesn't like a font icon mapped to \e000

Moved the generic file icon to \e027 and put the no-longer-used history icon at \e000
More file types and a tweak to close #177
Small CSS tweak (use % instead of em)

Shouldn't change anything much… just make it a bit more obvious what we mean by a particular font-size choice.. as well as making it easier to dynamically modify it in the future,
Fixes #173 - but also a lot more than that…

Seems somewhere along the way, refreshing favorites from within the Favorites view broke. Also, viewing historical versions from within the favourites view broke.

This caused a lot more changes than it sounded like, but I think it's all sane now.

This is a regression bug. We NEED more comprehensive tests.
Merge pull request #178 from SpiderOak/issue-160-nexus7-icons

Fixes #160 - missing nexus7 icons
Merge pull request #179 from SpiderOak/issue-173-faves-confirm-once

Fixes #173 - but also a lot more than that…
Merge branch 'master' into issue-128-storing-b32-usernames
Merge branch 'master' into issue-128-storing-b32-usernames

Had to do some manual reconciliation, certainly because I'm handling the
pull requests out of order.

Conflicts:
	src/views/FilesView.js
Merge pull request #176 from SpiderOak/issue-128-storing-b32-usernames

Fixes #128 - non-collision and multiple users
Merge conflict resolved and a version bump.
Merge branch 'master' into issue-143-passworded-sharerooms

Conflicts:
	src/views/FilesView.js
Reconcile the FilesView.js merge conflict.

This is the only combination that seems to function correctly, though I'm
not sure why it's right.