Add support for GPT: 1. When the parition type is not an integer, try to parse the type    as an UUID. If that succeeds, map the UUID to chunk_e. 2. For GPT partitions, pass the type constructed in point 1 above    to Add_Chunk.
Add support for GPT:
1. When the parition type is not an integer, try to parse the type
   as an UUID. If that succeeds, map the UUID to chunk_e.
2. For GPT partitions, pass the type constructed in point 1 above
   to Add_Chunk.

While here, fix the MBREXT case by only checking if the first 3
characters are MBR. This avoids duplication.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase