# exclude_projections fails when using only one index

When the target file of `exclude_projections = `

contains only one scalar value, the result of `numpy.loadtxt(fname).tolist()`

is a scalar. This makes the rest of the processing crash.

`exclude_projections = `

contains only one scalar value, the result of `numpy.loadtxt(fname).tolist()`

is a scalar. This makes the rest of the processing crash.