Imports of package tilecover

PathSynopsis
errorsPackage errors implements functions to manipulate errors.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/paulmach/orb
github.com/paulmach/orb/maptilePackage maptile defines a Tile type and methods to work with web map projected tile data.
mathPackage math provides basic constants and mathematical functions.
sortPackage sort provides primitives for sorting slices and user-defined collections.