Add optional 'target' attribute for <button>

[ClementParis016]

<button> components needs the ability to be passed a target attribute (that will be passed to the resulting <a> element), which could be set to _blank for use in the "view in browser" version of emails.

See foundation/foundation-emails#432 for discussion.

[rafibomb]

Thanks for the PR! Do you know it's causing Travis to fail?

[ClementParis016]

Yep, tests on characters encoding are failing. But I don't think it's related to the code I wrote because when I forked the repo and ran the tests for the first time, they were already failing.
I will double check that later in the day and let you know.

[ClementParis016]

@rafibomb indeed, the failure doesn't come from my additions since the exact same tests are also failing for master on my fork.
Could it be related to #37 in any way?

EDIT: these tests you've added at 41e9e58 never passed, but #37 is definetely addressing this issue.

[rafibomb]

Sounds like it is fix-character-encoding. @kball is this something we can revert for now so the test pass?

[rafibomb]

Great PR BTW! From now on we'll be directing PR's for bug fixes to the develop branch and new features to the next point release (2.2.0 branch currently)

Merging this here - thanks!

[kball]

@rafibomb yeah those tests should just be on the branch where we're working on the encoding. You can revert them in develop/master

[rafibomb]

@ClementParis016 It seems like we'll need to set this up for the menu items as well foundation/foundation-emails#465 Is that something you can help with? The method should be much the same.

Thanks!

[ClementParis016]

@rafibomb Yep, it seems to be a quick one, I will submit a new PR in a few ;) (not sure if we could re-use this one ? I'm quite new to contributing on open source projects)

[ClementParis016]

Done, #54