unit: Update documentation, create examples, and comment types
Updates 90.
DELETE
unit/README.md
-# Gonum unit [![Build Status](https://travis-ci.org/gonum/unit.svg)](https://travis-ci.org/gonum/unit) [![Coverage Status](https://coveralls.io/repos/gonum/unit/badge.svg?branch=master&service=github)](https://coveralls.io/github/gonum/unit?branch=master) [![GoDoc](https://godoc.org/github.com/gonum/unit?status.svg)](https://godoc.org/github.com/gonum/unit)
-
-Package unit provides a set of types and constants that facilitate the use of the International System of Units (SI).
-
-## Issues
-
-If you find any bugs, feel free to file an issue on the github issue tracker. Discussions on API changes, added features, code review, or similar requests are preferred on the gonum-dev Google Group.
-
-https://groups.google.com/forum/#!forum/gonum-dev
-
-## License
-
-Please see github.com/gonum/license for general license information, contributors, authors, etc on the Gonum suite of packages.

MODIFY
unit/doc.go
unit/doc.go
// func main(){
// t := 300 * unit.Kelvin
// p := 5 * unit.Bar
-// rho := UnitDensity(p, t) // gives compile-time error
+// rho := UnitDensity(p, t) // compile-time error
// }
// gives a compile-time error (temperature type does not match pressure type)
// while the corresponding code using float64 runs without error.
// rho := Float64Density(p, t) // no error
// }
// Many types have constants defined representing named SI units (Meter,
-// Kilogram, etc. ) or SI derived units (Bar, Milligram, etc.). These are
-// all defined as multiples of the base unit, so, for example, the following
-// are euqivalent
+// Kilogram, etc. ) or SI derived units (Bar, Hz, etc.). The Unit package
+// additionally provides untyped constants for SI prefixes, so the following
+// are all equivalent.
// l := 0.001 * unit.Meter
-// k := 1 * unit.Millimeter
+// k := 1 * unit.Milli * unit.Meter
// j := unit.Length(0.001)
//
// 2)
// used, however, to create the unit of 'Slide', because in this case slide
// is just a measurement of area. Instead, a constant could be defined.
// const Slide unit.Area = 0.001875 // m^2
-// var WhiteBloodCellDim unit.Dimension
-// func init(){
-// WhiteBloodCellDim = unit.NewDimension("wbc")
-// }
-// type WbcPerArea float64
-// func (w WbcPerArea) Unit() *Unit{
-// return unit.New(float64(w), unit.Dimensions{WhiteBloodCellDim: 1, unit.LengthDim: -2})
-// }
-// func main(){
-// v := WbcPerArea(15)
-// fmt.Println(v.Unit()) // prints: 1.5e+01 m^-2 wbc
-// }
// Please note that Unit cannot catch all errors related to dimensionality.
// Different physical ideas are sometimes expressed with the same dimensions
// and Unit is incapable of catching these mismatches. For example, energy and

unit: Update documentation, create examples, and comment types

Updates 90.