Add ability to programmatically
extract info from libnetcdf.settings
API is below.
I have made this API public yet
by adding it to netcdf.h. I will
do that when everyone is agreed on the
proper API.

extern const char* nc_settings(const char* key); /*get value of a specific key */
extern const char** nc_settings_all(); /*get all settings in envv format */
extern void nc_settings_reclaim(); /* reclaim all space and clean up */

Envv format is
{key,value}*,NULL

Also added test: nc_test/tst_settings.c
Conflict resolution