* Add min-width to body when printing

This should address some inconsistencies between browsers when printing. It applies a min-width to the body so that the content better resembles what your might see on your screen. I've made it a variable for easy customizing, too.

* Don't underline buttons when printing

* Add basic print styles for page and body size to create a semi-consistent print experience across browsers

Bootstrap itself doesn't use any `::first-letter` or `::first-line`
styles. These selectors also cause(d) problems in IE11 (see
https://github.com/h5bp/html5-boilerplate/pull/1799) and currently cause
a nasty rendering bug in Chrome where the first letter is vertically
shifted (see https://github.com/twbs/bootstrap/issues/21771)

As h5bp has now removed these as well, no need to keep and comment them
out. See https://github.com/h5bp/html5-boilerplate/issues/1961 /
https://github.com/h5bp/html5-boilerplate/pull/1962

`*::first-letter` causes problems in IE11 - only prints first page of a
multi-page document

With apologies, copy/paste error following on from trying to fix conflicting Hound/Travis checks for https://github.com/twbs/bootstrap/pull/20821/ slipped through before I noticed them.

most notable change:
- fixes print/print preview crash in IE11 (caused by `*:first-line`
selector)

[skip sauce]

Remove print-specific img max-width:100%; style so that Google Maps and other widgets print correctly

See https://github.com/h5bp/html5-boilerplate/issues/1741
X-Ref: #1506

[skip sauce]

Fix #17052

* Relative URLs were output as-is, which is suboptimal or even confusing for end-users
* Ditto for fragment identifiers
* Outputting long URLs inline with prose isn't good UX

JavaScript could potentially help with this (e.g. http://alistapart.com/article/improvingprint).
However, we're not currently interested in trying to tackle the hard problem of fancy print stylesheets/views
(particularly given the level of cross-browser inconsistency when it comes to printing).
So let's just keep things simple, vanilla, and unsurprising,
which should also make it easy for others to add their own print fanciness on top of Bootstrap.

Forcing black-and-white text & backgrounds is too harsh. Printing speed isn't everything.
Users or authors can easily enable grayscale themselves if need be.

Chrome fixed the bug as of v37:
https://code.google.com/p/chromium/issues/detail?id=282918

Refs:
    https://github.com/h5bp/html5-boilerplate/commit/57be193031b95b003b96efe9eba7a4db7f58f4e1
    https://github.com/h5bp/html5-boilerplate/issues/1477

* Updates `.table` to always enforce a solid white background
* Update button groups and dropdowns to always use black carets
* Add a 1px solid black border to labels (in the future we should add a
border to these perhaps for better printing)