Add coveralls support.

[info] 11/13   psp.tests.CountOperationsSpec.composite.agreement    Success
[info] 12/13   psp.tests.CountOperationsSpec.composite    Success
[info] 13/13   psp.tests.CountOperationsSpec.   Success
scct: [psp-view] Generating coverage report.
[info] utest
[info] -----------------------------------Results-----------------------------------
[info] CountOperationsSpec$   Success
[info]     composite    Success
[info]         agreement    Success
[info] ViewSpec$    Success
[info]     bitset   Success
[info]     string   Success
[info]     array    Success
[info]     map    Success
[info]     seq    Success
[info]     vector   Success
[info] NatSpec$   Success
[info]     zip2sum    Success
[info]     zip3sum    Success
[info] Tests: 13
[info] Passed: 13
[info] Failed: 0
[info] Passed: Total 12, Failed 0, Errors 0, Passed 12
[success] Total time: 27 s, completed Feb 17, 2014 12:59:14 AM