Improve display of connected accounts and avatars.
When no account attached, show platform icon where avatar is + don't show avatar at all.
Fix whitespace around images; remove the need for a magic number.
Move platform names below the account names; fix bitcoin button.
remove obsolete style
fix sizes of images in Account Tab
make it look more like the original mockup

also fixes #2271
fix the spacing between a platform's name and its icon
push platform icons a bit more to the right
Merge pull request #2265 from gittip/issue-2154

Improve display of connected accounts and avatars.