Fix cap drop issues with lxc

This uses "," instead of spaces so that the flags are parsed correctly
and also does not do a strings.Split on an empty string because
strings.Split will return a slice with one element, and empty string
causing parsing to fail when it validates that the cap exists.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Use : to split caps in sysinit flags
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Skip whole dir dockerignoring with warning

Fixes #7093
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
integration-cli: add more tests for BuildAddTar

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
integration-cli/TestBuildAddTar: generate context from test

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
integration-cli/TestBuildAddTar: embed Dockerfile

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
Reorganize and clarify the DOCKER_BUILDTAGS docs

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Add AUDIT_WRITE cap

Fixes #6345

Thanks @larsks for outstanding investigation

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
[DOCS] replace foo/bar with concrete names

namespaces are not well documented, and I had to jump around to other docs. replacing `foo/bar` hopefully makes what's going on here a bit more obvious.

Docker-DCO-1.1-Signed-off-by: Tim Ruffles <timruffles@gmail.com> (github: timruffles)
Typo changes to docker-run-1.md - changing '-' to '--' where approp.

Docker-DCO-1.1-Signed-off-by: William Henry <whenry@redhat.com> (github: ipbabble)
Merge pull request #7181 from timruffles/patch-3

[DOCS] replace foo/bar with concrete names
pkg/units: Using 'case' instead of trickled ifs

Seems the perfect case for 'case' ;).

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
Merge pull request #7148 from tianon/buildtags-docs

Reorganize and clarify the DOCKER_BUILDTAGS docs
pkg/units: Standardized supported sizes

May make sense that both `FromHumanSize()` and `RAMInBytes()` support
the same units. Added 'PB' to the RAMInBytes regex.

Also updated tests.

Note: int64 is overflowed on quantities >= EB

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
pkg/units: Refactor regexp.Compile to init()

No need to recompile a fixed regular expression each time the function
executes. Abstracting it to the `init()` method.

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
pkg/units: Compacted var declaration and initialization

No need to have two lines. The type is even explicit when type casting
to `float64(size)`

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
pkg/units: Moved 'units' out of function

No need to initialize every time the function executes since it works as
a catalog.

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
pkg/units: Refactored common code to single func

Both functions perform the same logic and they just vary on the base
multiplication units. We can refactor the common code into a single
place.

Docker-DCO-1.1-Signed-off-by: Francisco Carriedo <fcarriedo@gmail.com> (github: fcarriedo)
Test on building from GIT url

Also I added fake git server to utils
Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)
Fix incorrect path in ENTRYPOINT example

The ENTRYPOINT example uses "/usr/bin/ls" as path, but `ls` is located at `/bin/ls`.

Docker-DCO-1.1-Signed-off-by: Sebastiaan van Stijn <github@gone.nl> (github: thaJeztah)