Split translations of "Tor check" in two lines when needed

As discussed here https://mailman.boum.org/pipermail/tails-l10n/2015-January/001876.html we would need a CSS modification in order to be able to translate “Tor Check” on https://tails.boum.org/news/index.en.html into other languages.

Proposal is to add a class to the button, example “twolines”.

Inherited CSS is then:
`
#tor_check a span {
position: absolute;
right: 0.7em;
bottom: 10px;
font-family: “Century Gothic”,“Avant Garde”,Avenir,TeXGyreAdventorRegular,“Heiti SC”,“Heiti TC”,AppleGothic,sans-serif;
font-weight: normal;
color: #FFF;
text-align: right;
font-size: 2.29em;
line-height: 1.1em;
}`

We should add:

`
#tor_check a span.twolines {
top: 0.3em;
width: 70%;
left: 30%;
text-align: left;
}`

All of that code should be double-checked, simplified as much as possible, and integrated in our current CSS.

Translators could be asked to provide the relevant strings for testing.

Feature Branch: doc/8798-torcheck-css-split

Original created by @u on 8798 (Redmine)