Error puked out when we should provide a useful message

[mjordan]

When MIK can't find the input CSV file, it pukes something like this out to the user:

Fatal error: Uncaught exception 'RuntimeException' with message 'SplFileObject::__construct(M:\Le Soleil\Missing issues from VPL\Missing issues from VPL_Le Soleil
 de Colombie): failed to open stream: No such file or directory' in M:\mik_mark\vendor\league\csv\src\AbstractCsv.php:128
Stack trace:
#0 M:\mik_mark\vendor\league\csv\src\AbstractCsv.php(128): SplFileObject->__construct('M:\\Le Soleil\\Mi...', 'r+')
#1 M:\mik_mark\vendor\league\csv\src\Reader.php(263): League\Csv\AbstractCsv->getIterator()
#2 M:\mik_mark\vendor\league\csv\src\Reader.php(217): League\Csv\Reader->getRow(0)
#3 M:\mik_mark\vendor\league\csv\src\Reader.php(184): League\Csv\Reader->getAssocKeys(0)
#4 M:\mik_mark\src\fetchers\Csv.php(91): League\Csv\Reader->fetchAssoc()
#5 M:\mik_mark\src\fetchers\Csv.php(128): mik\fetchers\Csv->getRecords()
#6 M:\mik_mark\mik(131): mik\fetchers\Csv->getNumRecs()
#7 {main}
  thrown in M:\mik_mark\vendor\league\csv\src\AbstractCsv.php on line 128

How scary! We should provide a useful message saying something like "Can't find input CSV file specified in the [FETCHER] section of your configuration file."