Add option -K Key (--key Key) to specify one or more keys to output.
See discussion: http://dev.exiv2.org/boards/3/topics/1983?r=1987
#1053. Added new option
K key for exact Key match (not grep as -g). modifier - (stdin/stdout) to insert/extract
Added long versions of all options (eg --key = -K)
Added Command Summary to exiv2.1
Work in progress: exiv2.1 documents features which are not yet implemented:
- modifier R (roundtrip) to insert