Let it float

• Lots of bug fixes
• New --check option to check for dependencies
• Removed non-core Perl module dep Time::Piece
• Handle different GFA names in Spades 3.11.0
• More checking of --kmers to ensure no overly long ones used
• Detect machine RAM
• Link to docker container
• Backwards compatible to older Pilon now
• FIx float/int problems with --ram and --mincov
• Increased default overlap for FLASH to 20
• Only keep .gfa file and call it contigs.gfa
• The very cool --depth subsample read feature is now default 100