dust sort is now more predictable as it orders first by size and second
by name.
Walkdir still gives different iteration orders on different systems so
all output is not entirely predictable
Fixes#9https://github.com/bootandy/dust/issues/9
Instead of printing the all sub tree leaves only the last leaf is now
printed. See readme change for example
The flag '-p' was added to print the sub tree the old way
Advised to use walkdir by burntsushi as using recursion on file systems
can blow the stack.
walkdir is slower but allows the code to be cleaner and more reliable
Also experimented with ignore but locking the hashmap resulted in
similar performance to walkdir but with much uglier code.
Several tests for recursive dirs, hard & soft links.
Tests use the tempfile project.
Personally I find the tests hard to read. Am considering adding a
'--no-color' output option as this will make the tests much more
readable. (Currently we have to call format_string to get the matching
colors and if a test fails the diff is very hard to read).
andy.boot