[#2444] Add support to build binaries on OSX

Problem
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We need to build python binaries on OSX

Changes
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This only required to update the paver.sh script as done in brink.
I have removed the duplicate detect_os script. It was introduced for the time when paver.sh was loaded from external brink repo.

For now only OSX 10.8 is supported.. but I hope it will also work with 10.9....
In the future we might want to build on 10.7 and use the same binaries for 10.8 and 10.9...

We need OSX so that developers can work on the project ... and usually the have recent or previous versions.

We also want to support OS X for the client part... so the plan is to support OS X in production :)

How to test
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reviewers: @dumol 

this is just to let you know about the changes.

I will work on updating our code to work on OSX and will come back with a review for a server release.
Thanks!