Create option to continue on non-blocking errors

[ericcornelissen]

Some errors don't prevent the program from running, e.g. a file is not found, but the user may want the program to stop anyway. Hence a few things need to be done:

• Decide default behaviour:
  • Stop on non-blocking errors
  • Continue on non-blocking errors
• Make it so that the program doesn't continue on a non-blocking error
• Implement functionality that allows the program to continue upon a non-blocking error

[ericcornelissen]

The default behaviour should be to continue on non-blocking errors, the reasoning being as follows: if a non-blocking error occurred - e.g. one file cannot be written to - it is not a problem if other files are written to. Moreover, if wordrow is run again with the same/a similar list of arguments to write to the file that failed before, the files that where previously written to won't be changed any further.