Build stdin with compress

[dnephin]

• Fixes'--compress', '-f -' and context do not play along #212
• Branched from expose config credentials without needing the Cli #227 (only the last commit is new)

Compress after the archive is rewritten.

[codecov-io]

Codecov Report

Merging #233 into master will increase coverage by 1.34%.
The diff coverage is 17.39%.

@@ Coverage Diff @@## master #233 +/- ##
==========================================
+ Coverage 46.98% 48.33% +1.34% 
==========================================
Files 172 172 Lines 11693 11710 +17 ==========================================
+ Hits 5494 5660 +166 + Misses 5882 5692 -190 - Partials 317 358 +41

[tonistiigi]

0c950fe LGTM

Could move that compress function to the moby/archive package but don't want to slow this down with vendoring. But could be a follow-up cleanup later.

[vdemeester]

LGTM 🐮

[thaJeztah]

I'm removing this from the 17.06.1 milestone; the refactoring taken from #227 probably are not needed for 17.06.1, so if we need just the fix, we may need a different implementation for the 17.06 branch

(let me know if you don't agree though 😃 )

[dnephin]

There is no way to test this properly without the refactoring. So if we want the fix I think we need to take the refactoring as well.

[thaJeztah]

I opened an internal issue for discussing; we need to outweigh the importance of this fix against the amount of changes required 👍

[dnephin]

rebased

[thaJeztah]

LGTM