fixed: seg-fault where really big commands were used
fixed: seg-fault where really big commands were used

The issues was a fixed-size buffer for the command.  Any command larger
than 2046 chars would crash.  Adjusted the code so the default size is
2k, but will re-size the buffer only when a command is too big.

Signed-off-by: Mark Nicholson <8d4a425c9e0ad7c7b6af22eb501c109304c1d477@gmail.com>

mark-nicholson/python-editline,mark-nicholson/python-editline,mark-nicholson/python-editline