archivist: CRAN 1.7

From NEWS:

• The order of parameters in asearch has changed!
• Added graphGallery for self-contained examples
• aread allows for single MD5 hash (which will be read from the default repo)
• asearch allows for only patterns (will be searched in local repo)

• ahistory has now 'artifact' argument instead of 'obj'

• Added tests.

• Removed unnecessary dependencies - now archivist is free of dependencies.
• shiny package is in Suggests so you should load that package before running shinySearchInLocalRepo function.
• Move saveSetToRepo with a new function loadSetFromRepo to the github.com/pbiecek/archivist2 repository.