remove unused util functions
Fix mem leak caused by not properly freeing bson

ejdbcommand() allocates a BSON struct in c code which needs to be freed by calling bson_del.
This is in contrast to the places where the BSON structs are allocated from within go and need
not be freed.
Add methods for export and import

Ejdb.Import() wraps ejdbimport()
Ejdb.Export() wraps ejdbexport()
Remove debug output
Merge branch 'develop'