Set fill gradient ID using attribute instead of inline style

It causes than the original value like "url(#gradient-name)" is
preserved. When inline style is used, value seems to be changed to
"#gradient-name" what causes a problem when SVG is extracted and
rendered in a separate page.
set SVG plot element fill background w/attribute

Use attribute instead of style.
readme.md : remove couchdb related install steps.
solar-system: set fill with attribute, not style
solar-system metadata:  viewPortDrag is necessary

Otherwise dragging causes NaN SVG attribute generation
Move invalidatingChangePre/PostHook to property-support module

[#51900021]

Not sure if conceptually this is the best place, but it will help a
lot while working on a separate modules for output and parameters
support.
Extract duplicated code and create ParameterSupport mixin

[#51900021]
Extract duplicated code and create OutputSupport mixin

[#51900021]
Extract duplicated code and create defineBuiltinProperties module

[#51900021]
Add tests of OutputSupport and ParameterSupport modules

[#51900021]

Note that they are old tests in fact. The only difference is that now
we don't use MD2D molder, but we construct an empty object, then use
mixins and work on it. So it's independent of MD2D and tests new mixin
modules.
Implement LabModelerMixin - tool for new model types

[#51900021]

This module should be useful for all Lab model types. It combines
PropertySupport, ParameterSupport and OutputSupport, as well as
defines builtin properties using provided metadata and units
definiton.

Of course this can be done manually, but this provides easy, ready-to-
go configuration, which is used by all model types at the moment.

When a model doesn't need all these features (mixins) or it needs
something special - this still can be a hint how to do it.
Rm duplicated code from Signal Generator modeler, use LabModelerMixin

[#51901989]
use --all option for git add for gh-pages generation
release archives now linked from public/version

If gh-pages branch not already setup for public dir
create branch named 'public' for public dir

Makefile: make clean-archives
Cleans up version dirs used for archives

Archived resources served from:

  http://<hostname>/version/0.5.2

Archived tarball served from:

  http://<hostname>/version/0.5.2.tar.gz
genetic-elements-renderer.js  use attr('fill') instead of style('fill')

Generated SVG was not rendering outside of interactive application.
Needed to get snapshots working.
Makefile: clean-public also ignores version dir
get all zone records when listing AWS servers

Display hostnames when running: thor cloud:list even
when the zone record list is large.

Just requesting all results in a paginated type of
response from Route53. Using the all! method in Fog
actually gets all the records. 

This is inefficient. It should instead be possible
to get a DNS record from Route53 with fog by specifying
a record type of "A" and the right IP address.
AWS: generate target correctly in server_prologue

Fixes thor tasks for creating and re-creating servers.

Example:

  thor cloud:recreate <hostname>
cap <target> deploy:setup: provide more instructions
Gemfile updates: fog, guard, guard-sass, guard-coffeescript