Utils:get_tempfile: use Tempfile from Ruby 1.9

Not sure why that wouldn't work,
but please let me know if you've seen it fail!
remove unused colorize dependency
remove trailing spaces
minor style adaptations

We're already using 1.9 hash syntax, might as well go all the way.
Also aligning a bit.
correct Utils::get_timstamped_key_name typo
remove Utils::get_utc_timestamp indirection
remove Utils::get_timestamped_key_name indirection
remove unused Utils::ungzip_file
avoid 3 newlines for consistency

Sorry, turns out the slightest details can throw me off.
I have to stop procrastinating now.
database/*: remove indirections
introduce report path