added exchange_rank to allow tomopy to process exchange1, exchange 2 etc.
added exchange_rank to allow tomopy to process exchange1, exchange 2 etc.
added exchange_rank (int) to direct tomopy to process exchange 1, exchange 2 etc.
added exchange_rank (int) to direct tomopy to process exchange 1, exchange 2 etc.
set exchange_base once and forced exchange_rank to int
Merge pull request #38 from decarlof/master

Added exchange_rank to direct tomopy to the dataset to reconstruct