stalker.pl: fix: removed trailing whitespaces
stalker.pl: fix: only add index if it doesn't exist
stalker.pl: fix: dynamically create or upgrade database based on missing tables or columns
stalker.pl: fix: allow dynamically creating indices for future tables
stalker.pl: bumped version to 0.9

Added copyright for myself (Stefan Wold). Version history updated.
Merge pull request #12 from Ratler/various_fixes

Dynamically create or upgrade database and indices