fix import path

add example

doc fixes

add package documentation

change Item to be an interface

rename strategy to select, export ItemsBySize

package clients should decide if and in which order the input should be sorted,
don't do it automatically in pack.

fix cmd build task

add gitignore

add coverage output to .build.yml

return errors for bin methods

only create bin in newBin, remove adding of item

add blockSize parameter and some help text

rename item field Path to Data and change type to []byte

moved fit.go to pack.go

added .build.yml

initial commit