Add Dockerfile for building Mesos from source.

Review: https://reviews.apache.org/r/25369
Remove dead source file (not referenced in makefile)

Review:
Fixed build error caused by overloading socket call on CentOS 5.

Review: https://reviews.apache.org/r/28854
Modified mesos configure.ac to set $with_svn to `brew --prefix subversion` for OS X.

Review: https://reviews.apache.org/r/28721
Modified libprocess configure.ac to set $with_svn to `brew --prefix subversion` for OS X.

Review: https://reviews.apache.org/r/28722
Added a hash function for Node.

Review: https://reviews.apache.org/r/28869
Fixed a long-standing performance issue in libprocess' SocketManager.

Review: https://reviews.apache.org/r/28838
Extended error message for module manager when library loading fails.

Review: https://reviews.apache.org/r/28764
Removed dead header file (not referenced in makefile)

Review: https://reviews.apache.org/r/28878
Added a benchmark to test large number of links for MESOS-2182.

Review: https://reviews.apache.org/r/28871
Fixed a regression within libprocess link management.

Review: https://reviews.apache.org/r/28887
Added comment for getIP function declaration

Review: https://reviews.apache.org/r/28788
Added a TODO in the master for an allocator bug.

Review: https://reviews.apache.org/r/28812
Added missing includes to sorter.hpp.

Review: https://reviews.apache.org/r/28813
Updated the allocator interface to enable unit testing.

Review: https://reviews.apache.org/r/28814
Converted an initial DRF integration test to a unit test.

Review: https://reviews.apache.org/r/28815
Moved DRFAllocatorTest.PerSlaveAllocation to a unit test.

Review: https://reviews.apache.org/r/28816
Moved DRFAllocatorTest.SameShareAllocations to a unit test.

Review: https://reviews.apache.org/r/28817
Moved ReservationAllocatorTest.ReservedResources to a unit test.

Review: https://reviews.apache.org/r/28818
Moved ReservationAllocatorTest.ResourcesReturned to a unit test.

Review: https://reviews.apache.org/r/28819