AV4

Apart from various cleanups, this version is mainly about

• artifact-version: 4 (include definitions repo: and ref: in metadata for systems and strata)
• @rjek provided a fix for ybd failing to handle nginx compressed downloads
• @jjardon added support for running ybd on Arch Linux

e334c50 Add definitions repo+ref to .meta, from artifact-version: 4 onwards
77ad4e4 Only report skipping once
2b50266 Delay sandbox creation - may help for #139
fde2f67 Fix #175 using Eli Bendersky's Counter class
52e802d Gah... fix 543b654
543b654 Add 'skipping compose' message
8aed0f8 Lose a couple of lines
e403cfb Reverse logic, lose a line
62fedc2 Fix comments in default ybd.conf
7a3cb92 Fallback to copy all files if metadata copy fails
63e3567 Shorten some lines by 'from app import...'
739631b Shorten lines by 'from app import...'
016398f Make 'contents' field dict, containing splits if any
d33e0c8 Artifact-version: 4, include repo: & ref: in meta
13ab7a0 Standardise .meta artifact|files => artifact|components
dc24b2f Cache-key only in .meta from artifact-version 2
2b3786f System cache-key varies with default-splits
25c58d2 Report actual 'kind' in splitting log
b43bb44 Clarify what the try/except is for
41e064a Lose a couple of lines
4304456 Rename element => product
a1c8bc3 Don't include anchors in parse output
f00e6cd Output internal format as yaml
b09eeb4 Revert "Attempt fix for #218"
94461f4 KBAS was using response.raw, instead of response.content
b2f0866 Missed another absolute /static
f34bd8a Use relative path for css
5ccb421 Exit 1 on calling with no params
38c2220 Merge pull request #219 from jjardon/jjardon/arch
155c828 install_dependencies.sh: Add support for Arch
b4e6cdd Attempt fix for #218
5c2c9a3 Exit if YAML parsing fails on any definition
4972e30 Check for installation success
8959629 Check that apt|yum|dnf is found
dace4d1 Disable splitting by default, because it's slower
6aa0ffb No need to exit if bootstrap artifacts missing
42a2cd7 Drop 'Cache key is' text
5300c64 State where surprise exceptions happen
5ed3cba Exit on missing morph file
3155ba9 Only support split systems from artifact-version 3
0d2d04f Pep8
779d3e7 Force new cache-key for split systems
461d282 Create runtime systems by default
7c73938 Move checkboxes so they are easier to scan
f33c244 Fixes #163 Warn if any specified .morph file is missing
950d6aa Remove wrangler.py