Cholesky-2.3

• Fixed mincLmer reinit (formula out of scope bug)
• Improved mac install notes (issue #261)
• Defaults RMINC_LABEL_DEFINITIONS to null instead of empty string
  (issue #259)
• anatGetAll fails faster if the label defs are broken (issue #260)
• civet.readCBrain now supports columnsToKeep to pass to flattening
  code
• Add environment variable to configure where test data is located, useful
  for systems where internet isn't available.
• Improvement to FDR threshold selection in launch_shiny_RMINC
• Code for reading in a matrix of minc files mincTable. Supports
  file backed matrices for when your files are too big for your computers
  memory.
• Fixed reading QC for CIVET 1.1.12 experiments
• Fixed and streamlined the continuous integration (travis) build scripts
• Fixed all outstanding R CMD check and test issues