v0.2.20

• Added bbox= option to -clip and -erase commands for clipping/erasing using a bounding box.
• Added -rename-fields command.
• Use .cpg file (if present) to set dbf text encoding.
• Use dbf "language driver id" (if present and valid) to set dbf text encoding.
• Try to auto-detect dbf text encoding if other methods fail (limited to utf-8 and latin1)
• Support reading delimited text files with non-utf-8 encodings (using -i encoding= option).
• Remove byte order mark (BOM) when importing text files in utf-8 and utf-16.
• Fix a bug affecting -calc command.