added xunit formater support

[lfrodrigues]

Added xunit output formatter. Not sure I used the correct attributes for the elements but it was enough to make prospector work with shippable.

This will fix #32

[coveralls]

Coverage decreased (-0.43%) to 77.27% when pulling dd509fb on lfrodrigues:master into 8a03a50 on landscapeio:master.

[coveralls]

Coverage decreased (-0.43%) to 77.27% when pulling dd509fb on lfrodrigues:master into 8a03a50 on landscapeio:master.

[landscape-bot]

Repository health decreased by 0.45% when pulling dd509fb on lfrodrigues:master into 8a03a50 on landscapeio:master.

• 11 new problems were found (including 0 errors and 2 code smells).
• No problems were fixed.

[coveralls]

Coverage decreased (-1.2%) to 76.5% when pulling afaf753 on lfrodrigues:master into 8a03a50 on landscapeio:master.

[coveralls]

Coverage decreased (-1.2%) to 76.5% when pulling afaf753 on lfrodrigues:master into 8a03a50 on landscapeio:master.

[landscape-bot]

Repository health decreased by 0.04% when pulling afaf753 on lfrodrigues:master into 8a03a50 on landscapeio:master.

• 2 new problems were found (including 0 errors and 0 code smells).
• No problems were fixed.

[coveralls]

Coverage decreased (-1.2%) to 76.5% when pulling 1380b38 on lfrodrigues:master into 8a03a50 on landscapeio:master.

[landscape-bot]

Repository health decreased by 0.01% when pulling 1380b38 on lfrodrigues:master into 8a03a50 on landscapeio:master.

• 1 new problem was found (including 0 errors and 0 code smells).
• No problems were fixed.

[lfrodrigues]

Any comment on this PR? I would really like to have this integrated, should I change anything?

[carlio]

@lfrodrigues I merged it into the develop branch but I didn't realise that GitHub didn't update the PR, sorry! It's here: 1380b38 . The PR will probably only get updated when I merge develop into master I guess.

I'm going to make a new release soon* which will include this. Thanks for the contribution :)

* next week hopefully

[lfrodrigues]

ok cool!