first pass at using Context and PFM for the map tool.
[TST] add new tests for map
[ENH] add absmin and absmax to VectorOps and map tool.
[BUG] change getField() logic in GffRecord
[ENH] add str() method to QuickString
formatting
map uses PFM.
add nullValue and ColOp to ContextBase for Map
allow RecordOutputMgr to print a record followed by arbitray string
add methods to extract column from record by its col. number
add methods to extract column from record by its col. number (2)
add a Context for Map tool.
reduce QuickString DEFAULT_CAPACITY to 8 instead of 256 to save memory.
fix conflict
fix conflict.
fix conflict.
[TST] add tests for map