Multisite: Lowercase REQUEST_URI when matching paths.

props markjaquith, jeremyfelt.
fixes #26403.

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Network Admin: Case-insensitive comparisons for the network-site comparison in the bootstrap.

props jeremyfelt.
fixes #17168.

Built from https://develop.svn.wordpress.org/trunk@27725


git-svn-id: http://core.svn.wordpress.org/trunk@27562 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use Dashicon-style images for mime type icons. Actually moving to Dashicons via the font can be explored later, but has theme/plugin implications and requires too many changes to make it for 3.9. props melchoyce for the icons. fixes #26650.

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git-svn-id: http://core.svn.wordpress.org/trunk@27563 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Ensure buttons don't get overly tall in responsive views when a browser (oh, Firefox) enforces a line-height on buttons. props azaozz. fixes #27409.

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git-svn-id: http://core.svn.wordpress.org/trunk@27564 1a063a9b-81f0-0310-95a4-ce76da25c4cd