Added role parameter to JobTracker.

Now it's possible to specify the framework role by setting
mapred.mesos.role.  The default role is "*".

Review: https://reviews.apache.org/r/13092
Updated Mesos mapred-site.xml for Hadoop.

Review: https://reviews.apache.org/r/13077
Simplified os::hostname() in libstout.

Review: https://reviews.apache.org/r/11108
Included pre/post-package hooks in Hadoop tutorial.

Review: https://reviews.apache.org/r/11110
Allowed ending Hadoop tutorial early.

You may also skip the test part by exporting SKIP_TESTS (i.e., 'make
hadoop SKIP_TESTS=1').

Review: https://reviews.apache.org/r/11111
Added check for Python.h in configure script.

Review: https://reviews.apache.org/r/11114
Switched to more portable paths for tutorial test.

Review: https://reviews.apache.org/r/11115
Shuffle offers before sending to frameworks.

This helps ensure fair allocation of resources.

Review: https://reviews.apache.org/r/11121
Write Mesos JobTracker stats to state file.

Review: https://reviews.apache.org/r/11165/
s/hadoopJobs/jobs/g in Hadoop scheduler.

Review: https://reviews.apache.org/r/11489
Refactored Hadoop job completion.

Review: https://reviews.apache.org/r/11603
Stop tracker timer when we terminate tasks.

Review: https://reviews.apache.org/r/11604
Added --enable-debug configure flag.

Review: https://reviews.apache.org/r/11605
Slave ping timeout may be increased by flags.

Review: https://reviews.apache.org/r/12885
Use XZ (LZMA) for package on Linuxes.

Review: https://reviews.apache.org/r/11112
Turned down noise from ZooKeeper.

Review: https://reviews.apache.org/r/11127
Fixed hadoop 0.20.205.0 dist.

Review: https://reviews.apache.org/r/11662
Allowed specification of mininum slot count.

To ensure Hadoop jobs begin promptly, we can specify a minimum number of
'hot slots' to be available for use.  This addresses the TaskTracker
spin up delay that exists with Hadoop on Mesos.  This can be a nuisance
with lower latency applications, such as ad-hoc Hive queries.

Review: https://reviews.apache.org/r/12921
Fixed broken build on GCC 4.8 due to -Wall.

With GCC 4.8, Boost fails to build from '-Wunused-local-typedefs', which
is implied by '-Wall'.

Review: https://reviews.apache.org/r/11974/
Use hostname instead of IP for redirection.

In the Web UI, the redirection does not work for hosts where the local
interface address is not publicly accessible.  For example, with EC2 the
redirection will not work.

This change writes the Master's hostname into ZooKeeper, thereby
allowing the redirection to work with private IP addresses.

Review: https://reviews.apache.org/r/11975/