Merge pull request #8 from artpol84/master

Fix PMI shutdown problem with Hydra PMI
Buf fix: dmtcp_launch.cpp: fails when number of parameters exceeds 128
Fix --join for dmtcp_launch and dmtcp_restart.
HYDRA PMI: Fix logical expression that determines whether we want PMI shutdown or not.
intermediate commit. dmtcp_srun_helper now successfuly calls srun and MPI app is running ok.
However there is a DMTCP arror at app exita and no checkpoint/restart support yet implemented.
intermediate commit.
Now we can checkpoint application.
Problems:
1. restart wasn't implemented
2. Under ompi at exit there is an error message from srun helper saying about coordinator message mismatch.