Fixed double-declaration error.
Added 'pretty' log mode

Added special value for log_mode 'pretty' which uses Util::message for
printing colored output. Meant to be used in interactive mode, it's
the default in cf-sketch.pl.
log_level default to zero in interactive mode

By default set log_level to 0 in interactive mode, to prevent all
spuriour output. Gets modified accordingly by --verbose or
--veryverbose.
Added 'info' command

The 'info' command shows detailed information about a sketch. With -v,
it shows its API as well.
Fixed date.
verification in case package do not exist or installation failed
Merge remote-tracking branch 'upstream/master' into feature/cf-sketch-finish
Moved utility functions to cf-sketch.pl
Print API messages also on success.
uninstall and deactivate commands

Uninstall removes installed sketches, deactivating them in the process.
Deactivate only deactivates sketches, either by sketch name of by
activation ID.
Ability to specify options to the API on api_interaction.
Added utility functions for common query operations on the API.
Added optional indent parameter to pretty_print_json.
Output improvements overall.
Ability to specify activation ID.
Reimplemented run command, improved messages.
Implemented "remove params" command.
Implemented "define params" command

This is the command that allows defining param sets. Interactive mode is
not implemented yet, only reading from file for now.
Merge pull request #294 from zzamboni/feature/cf-sketch-finish

New commands run, define, remove, other miscellaneous improvements
regenerate.pl: remove File::Slurp dependency