Add test fixture for CSV file containing single column.
Clear temporary storage at the start of each test so that leaked storage files don't affect other tests but still hang around for someone running a single test who wants to look at them.
Add test that shows failure to upload a single column CSv file.
Guess harder when encountering CSV files that fail to be sniffed and attempt to detect single column CSV files by looking for tabs or commas.
Use modern exception syntax instead of ugly brackets and commas.
Use modern exception syntax instead of ugly brackets and commas (in a second place).
Merge branch 'feature/issue-725-fix-single-column-upload' into develop
Merge branch 'develop' of github.com:praekelt/vumi-go into develop