v0.2

Main improvements

• The restriction to phyloseq as input data is removed, there
  are now several ways of providing input data
• Custom coloring improved, more options
• Temporary files are cleaned up in most cases (except if used from the console)
• The special Perl import script is not needed anymore
• A tutorial was added
• Rendering now works on Windows

Other changes (from commit log)

• Captions are now possible in HTML output (with bookdown)
• Abundance summary functions can be configured
• snapshot_format is auto-recognized based on output file extension
• Krona Javascript can be included from remote sources and
  is minified by default to save space