* remote: remove unpacked dir
We've done a lot of optimizations lately, which made unpacked dir trick
obsoleted.
* local: save us a stat call in is_protected
* local: speedup checksum_to_path ~x5.5
* tree: walk: don't use os.path.join
It is ~5.5 times slower than joining by hand.
* dvcignore: optimize matching x10
On a repo with a dvcignore with 1 pattern and a directory with 400K
files, `dvc status` now takes ~8 sec instead of ~30 sec.
To achieve that, we make some assumptions about the paths formats that
we are dealing with, so we could use simpler logic instead of using
very slow `relpath`, `abspath` etc on every entry in a directory.
It is also clear that CleanTree behavior is inconsistent (even tests
expect very different outputs from it), so we will need to look into
this later.
Ruslan Kuprieiev
d77af8196e