Lager to v2.0
Merge pull request #368 from oldmantaiter/feature/lager-update

We will use a tag instead of the master branch as soon as there is a new lager release.
Change do_choose_write_nodes to accept the Include list.
Modify choose_write_nodes to accept an Include argument.
Rename parse_exclude to parse_inclusion.
Add Inc to new_blob.
Add the inclusion to the command parsing code.
Parse the inclusion list in the erlang code and actually use it.
Add the forceon option to the python code.
Complain if the requested replica is not found.
Add the master option to the disco and ddfs commands.
Add a test to distinguish between group_node_label and group_label.

When we run this test on a disco cluster with more than one node, we can
see the improvements of the group_node_lable over group_label.  With
group_node_label, for each intermediate step, one task is created on each
node and the inputs are processed locally.  With the later, only one
task is created on one of the nodes and all of the input is shipped to
that node.  If the size of the input files is large enough, we can see
significant improvements.
Add a test for using raw input data in the pipeline version.
Add a test to chain a set of stages to join two tables.

This test might fit better as an example than a test.  It examines the
interactions of the different stages to efficiently join two tables.
Let the tasks be combined and/or sorted before each pipeline stage.
Add a test for sorting and combining the inputs of a job.
Fix a missing argument when calling new_blob.
Merge pull request #371 from pooya/shayan/upstream_ddfs_change_fix

Shayan/upstream ddfs change fix
Merge pull request #372 from pooya/shayan/upstream_add_tests

Shayan/upstream add tests
Merge pull request #373 from pooya/shayan/upstream_add_master_option

Add the master option to the disco and ddfs commands.