Rename MSFragger to FragPipe

Changes:

• Renames functions for reading FragPipe output to tidy_FragPipe_
  for details:
  https://fgcz.github.io/prolfqua/reference/FragPipe.html
  See discussion #31

• Vignette "Quality Control & Sample Size Estimation" now uses R6 API

• Added "Model with Interaction" vignette based on IonStar dataset
  https://fgcz.github.io/prolfqua/articles/ModelWithInteractions.html

Install

install.packages("https://github.com/fgcz/prolfqua/releases/download/v0.4.2/prolfqua_0.4.2.tar.gz",
	repos = NULL)