[meta] support MPI and multi-device

[t-hishinuma]

• get/set device num. I/F
• enable option of mpicc in cmake : -DUSE_MPI
• Input MPI_COMM I/F
• implement BLAS Lv.1 implement multi-process BLAS Lv.1 #56
• implement global size of Dense
• implement BLAS Lv.2(Dense)
• Checking the working of CG in Dense (precon = none)
• implement comm_table of CRS
• implement BLAS Lv.2(CRS)
• Checking the working of CG in CRS (precon = none)