Add set_keys() ignore_errors flag

[Sjoerd Kerkstra]

• pimsclient version: 1.5.2

For Project.set_keys() there should be an 'ignore errors' flag. Currently an error is thrown if any pseudonym to set already exists. When adding many pseudonyms however, upon hitting any error, often part of the pseudonyms you were setting aready exist. Having to prune these away each time before re-running the script is annoying.

Add 'ignore_errors=False' which will print warnings instead of raise exceptions when trying to set existing pseudonyms

[Sjoerd Kerkstra]

Superseded by PIMS2