Added a '/__processes' endpoint.
Added a '/__processes' endpoint.

Review: https://reviews.apache.org/r/12528

andschwa/mesos,zmalik/mesos,neilconway/mesos,yuquanshan/customizedMesos,andschwa/mesos,Aman-Jain-14/customizedMesos,yuquanshan/customizedMesos,neilconway/mesos,zmalik/mesos,yuquanshan/customizedMesos,Gilbert88/mesos,Gilbert88/mesos,asamerh4/mesos,verizonlabs/mesos,gsantovena/mesos,dforsyth/mesos,jpeach/mesos,Aman-Jain-14/customizedMesos,andschwa/mesos,chhsia0/mesos,dforsyth/mesos,craimbert/mesos,chhsia0/mesos,yuquanshan/customizedMesos,abudnik/mesos,Aman-Jain-14/customizedMesos,asamerh4/mesos,asamerh4/mesos,zmalik/mesos,yuquanshan/customizedMesos,zmalik/mesos,abudnik/mesos,gsantovena/mesos,reneploetz/mesos,Gilbert88/mesos,asamerh4/mesos,reneploetz/mesos,reneploetz/mesos,abudnik/mesos,andschwa/mesos,neilconway/mesos,zmalik/mesos,chhsia0/mesos,yuquanshan/customizedMesos,Aman-Jain-14/customizedMesos,Gilbert88/mesos,gsantovena/mesos,jpeach/mesos,gsantovena/mesos,craimbert/mesos,jpeach/mesos,verizonlabs/mesos,dforsyth/mesos,craimbert/mesos,verizonlabs/mesos,craimbert/mesos,dforsyth/mesos,asamerh4/mesos,neilconway/mesos,gsantovena/mesos,zmalik/mesos,kaysoky/mesos,verizonlabs/mesos,dforsyth/mesos,yuquanshan/customizedMesos,andschwa/mesos,dforsyth/mesos,neilconway/mesos,kaysoky/mesos,craimbert/mesos,verizonlabs/mesos,gsantovena/mesos,verizonlabs/mesos,jpeach/mesos,Aman-Jain-14/customizedMesos,gsantovena/mesos,kaysoky/mesos,reneploetz/mesos,asamerh4/mesos,asamerh4/mesos,chhsia0/mesos,kaysoky/mesos,reneploetz/mesos,neilconway/mesos,jpeach/mesos,chhsia0/mesos,kaysoky/mesos,chhsia0/mesos,andschwa/mesos,jpeach/mesos,Gilbert88/mesos,reneploetz/mesos,Aman-Jain-14/customizedMesos,craimbert/mesos,abudnik/mesos,craimbert/mesos,andschwa/mesos,neilconway/mesos,kaysoky/mesos,chhsia0/mesos,dforsyth/mesos,abudnik/mesos,reneploetz/mesos,zmalik/mesos,jpeach/mesos,abudnik/mesos,abudnik/mesos,Aman-Jain-14/customizedMesos,Gilbert88/mesos,verizonlabs/mesos,Gilbert88/mesos,kaysoky/mesos