Bumped minimum R required version to 3.5 (sysdata.rda uses workspace format version 3)
Replaced testthat with tinytest for Unit Testing.
sgo_coordinates gained a couple of paramaters meant for geodetic coordinates.
Improved the speed of NGR conversions.
A little tidy-up of both code and documentation.
sgo 0.9.1
Fixed: Now, when converting from 2D BNG to 3D BNG, the input is first converted
to 3D by filling z with zeros. Previous versions just added zeros to the output.
Fixed: When converting from 2D to 3D coordinates with the same datum the z
column was not being filled with zeroes.
Fixed: Points right on the upper boundaries of the OSTN grid are considered
outside of the OSTN15 rectangle.
Fixed: Output text of the print function.
Improved slightly the speed of 3D calculations from/to BNG.
Improved some parts of sgo_transforms's documentation.