Added descriptive error message when KlustaKwik fails
Clarified --overwrite message and logic

Removed possibility for accidental file deletion with --cluster-only. Explicitly
stated what --overwrite does; returns False when there's an error rather than
charging blindly on, and only displays it when spikedetekt is run - --cluster-only
will now not display the error message...
Typo and grammar fixes
Added boundary checks for KK_MaskStarts / KK_MinMaxClusters
Print version number at SD2 start or on klusta --version
Quit if people are using legacy PRM parameters without KK_
Typo fix rc2 -> .rc2
Merge pull request #11 from klusta-team/more_usability

Usability improvements