Improve support of LAS 1.4

[Jean-Romain]

lidR 2.0.0 does not have a good support of LAS format 1.4. This issue serves as a todo list.

rlas::read.lasheader does not read all the data from a LAS 1.4 which render impossible a full support of LAS 1.4. Once rlas will have a full support of LAS 1.4 lidR will need some updates

• lascheck must be updated to consider the 1.4 specification and to take advantage of rlas 1.3.0
• LAS must be updated to take advantage of rlas 1.3.0
• print and summary must be updated to display more specific stuff including:
  • Global Encoding bits and their meaning
  • WKT string if any
• The support of WKT as CRS source must be added. See also rgdal::showP4
  • Read and interpret WKT string
  • Repect the Global Encoding WKT bit
• Update the vignette