* allow empty column lists in projection cursors;
* do another pass over the schema documentation and example code;
* add docs for the variable-length argument lists for WT_CURSOR:{g,s}et_{key,value}.
closes #409
* allow empty column lists in projection cursors;
* do another pass over the schema documentation and example code;
* add docs for the variable-length argument lists for WT_CURSOR:{g,s}et_{key,value}.
closes #409