add general support for keyword parameter.
remove tabs.
remove obsolete not-implemented -i switch.
extract db open/close into own functions.
create build-up and tear-down functions

- rename 'dset' style variables to 'd_opt_set' style variables
- made mode-style variables global
- replace exit() with tear-down function-calls.
add function for verbose output

- replace old occurrences of verbosity
  checking with new 'out'-function.
add creation of database (if not existent).
dry up the sql queries.
use c99 and remove unnecessary main-return stmt.