CSV Parsing: relax more parsing rules
Try to mimic Excel behaviour in parsing of invalid cell. Examples:
- "A" : A
- "B"_ : B_
- _"C" : _"C"
- _"D"_ : _"D"_
- "E" E : E_E
- _"F"_F_ : _"F"_F_
- "G"_"G" : G_"G"
- _"H"_"H" : _"H"_"H"
- "I"I" : II"
- "J""J" : J"J
- _"K""K"_ : _"K""K"_
- "L"" : L"