Slather 2.2.0

• Fix nil crash in project.rb derived_data_path
  bootstraponline
  #203
• Fix for correct line number for lines that are hit thousands or millions of time in llvm-cov.
  Mihai Parv
  #202, #196
• Generate coverate for multiple binaries by passing multiple --binary-basename or --binary-file arguments, or by using an array in .slather.yml
  Kent Sutherland
  #188
• Support for specifying source file patterns using the --source-files option or the source_files key in .slather.yml
  Matej Bukovinski
  #201
• Improve getting schemes. Looks for user scheme in case no shared scheme is found.
  Matyas Hlavacek
  #182
• Search Xcode workspaces for schemes. Workspaces are checked if no matching scheme is found in the project.
  Kent Sutherland
  #193, #191
• Fix for hit counts in thousands or millions being output as floats intead of integers
  Carl Hill-Popper
  #190