* Don't build unused Qt features; use all cores

* cmake does bootstrapping, too; comment unclear steps

* Use Docker comment syntax

* tab to space

Allow passing custom CMake arguments

* Use one job for MacOS Homebrew builds cache with Travis workspaces

* Brew build job needs to both feed to other jobs and cache between builds

* Move Linux jobs to the Final stage

With only 1 OSX job in S1, the Linux part is now the critical path and holds the build time back

* Including a custom libjpeg is no longer needed

Since https://github.com/opencv/opencv/pull/11497, OpenCV bundles its own

* (dummy commit to trigger rebuild)

* Added OpenSSL & different protocol support to FFmpeg backend
- Fixed Docker dependencies (both x86 & x86-64)
- Fixes bug #204

* Additional Fixes
- updates to OpenSSL build from scratch
- removed specific protocol
- Added neccessary dependency

* Fixed ./Configure command

* Updates for docker images:
- Added perl build from scratch
- Fixed wrong/redundant dependencies/paths
- Fixed & updated openssl installation

* Fixed Empty continuation lines bug & added comments

* fix inconsitent spacing

* Don't add perl 5.10 to PATH

* fix syntax error

* Fixed OpenSSL build fails in i686 Dockerfile due to buggy perl source

* Fixing manylinux docker entrypoint for i686 in 32 bit images

* ENTRYPOINT not needed, it only affects "docker run" invocations

* manylinux1 provides better libcurl for cmake

* manylinux1 provides the toolchain and git

git install fails in i686, too

* cleanup tar invocations

* nasm is not installed in manylinux1

* detect i686 in openssl configure

* move perl to a separate subtree as it's a private dependency

* rm it after library build

* comment unusual openssl build step

* avoid redundant work in perl build

* build each library in a separate dockerfile command for easier debugging

* comment custom i686 step

* update dockerfile README

* opencv now bundles libjpeg-turbo

and the separate's onre buid fails dueto expired certificate at https://kent.dl.sourceforge.net

Travis CI: Xenial is now the default Ubuntu in Travis

https://blog.travis-ci.com/2019-04-15-xenial-default-build-environment

Also: __sudo: required__ no longer is [Travis are now recommending removing the __sudo__ tag](https://blog.travis-ci.com/2018-11-19-required-linux-infrastructure-migration) because the sudo command is always available in Travis CI and there is no longer any way to turn it off.

Minor fixes in build logic

This reverts commit d4a51981.

cmake 3.14 can't find py3 installation when "python" points to Python 3 while cmake 3.9 can

Happened in https://travis-ci.org/skvark/opencv-python/builds/518179810 S1 jobs

Happened in https://travis-ci.org/skvark/opencv-python/builds/518836739 S1 jobs

Fixed typo

Fix OSX builds and migrate to Xcode 8.3

* Add a dedicated stage to each OSX build to download/build brew packages
* Remove bottle building logic and the corresponding trace output from the project build stage

* Reduce the number of command lines executed in most used functions
* List existing versions only when installing

* disable auto `brew cleanup`
* support formulae with disabled bottles
* install alongside to avoid "runtime dependents" update
  https://discourse.brew.sh/t/can-i-install-a-new-version-without-having-to-upgrade-runtime-dependents/4443

* fix built bottle & metadata cleanup when bottle is missing
* -e mode for before_cache step
* faster finish when already the latest version