imprement collective communications with MPI
rewrite mpi_red_type with macros
make x10rt_net_bcast() right

make x10rt_net_scatter() right

make x10rt_net_alltoall() right

make x10rt_net_allreduce() right
add mpi locks
Revert "changes about debug prints"

This reverts commit 4881e47361228cb49ee1eafc973fc6fb7ab1fa32.
imprement collective operations appends

add stubs for collective operations appends

test implement of scatterv

add tests for scatterv

mpi implement of gatherv

mpi implement of alltoallv

fix error messages

fix x10rt_logical.cc

make use the native implementation for MPI

add tests for scatterv and alltoallv

change a condition when native implementations of additional collective operations are used

rewrite mpi_red_type

add locks

add comments

add sbut codes

make Team.split's return values correct

rename some function names

rewrite template functinos to template constants(?)

add MPI 2.2 datatype support

add message type to allocate new team ids

remove some debug prints

fix a bug that x10rt_team_new is not work well when it is called in other than place 0.

fix a bug about x10rt_net_team_split

readd some lines
make x10rt_net_allreduce correct
fix typo
fix illeagal parts
add frees
add allgather and allgatherv
add lacking functions
add some useful wrapper functions
make Team hold where its member are
fix bugs
add a useful wrapper function
bugfix
remove debug print
add concept codes of OneSidedContext
add some useful wrapper functions