Added a smart default for read_csv [skip CI]
Added a smart default for read_csv [skip CI]


Former-commit-id: 3e21ef8c06047cc567539956f02a1948fdd64b46 [formerly 6d5f1eb1b0059e5f264490291ec4d2f6ab5ddb40]
Former-commit-id: e25600559954851c40d16423cc9f7a4f60d94264
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine