0.26.0

• Fix iagnostic position when parsing undefined symbol.
• Improve handle error in data provider.
• Don't apply CROSS join operator if one of the tables is empty.
• Update docs for new Data provider design.
• Remove un needed code for remove hidden selection after engine.
• Support exponentiation operator.
• Optimize the calling of data provider if table is empty.
• Implement Select ... INTO OUTFILE.
• Support INTO OUTFILE Terminated options and enclosed.
• Implement Select ... into dumpfile feature.
• Improve error messages when use options with dumpfile.