Add Regions support

[cannam]

Per #47 and the documentation at #46, add support for "regions" outputs, i.e. outputs that are structurally rather like notes but that lack the identifying RDF metadata or units necessary to be identified as representing note tracks.

[cannam]

(In branch feature/regions)

First I sprinkled the logic throughout FeatureUtilities to add a region type, identify appropriate feature data, and convert & return it. That's phase 1 done.

Next, the Angular stuff.

We need a new case block in analysis-item.component.html. For the moment I've copy-pasted this from the notes case, changing note to region throughout.

Now, something needs to define the new ugly-regions selector that we thus refer to. So I copy-paste app/visualisations/notes/notes.component.ts to regions/regions.component.ts, do a similar notes-to-regions replacement, and rewrite findVerticalRange to use unitless values. I don't expect this to work yet, because it's still creating a piano-roll layer, which looks for pitch values which our new regions don't have. But it should compile and load.

It doesn't, though. It compiles, but on page load I get errors in the console:

Error: Template parse errors:
Binding to event property 'onSeek' is disallowed for security reasons, please use (Seek)=...
If 'onSeek' is a directive input, make sure the directive is imported by the current module. ("
              [timeline]="timeline"
              [width]="contentWidth"
              [ERROR ->][onSeek]="onSeek"
              [notes]="item.collected"
              [duration]="getDuration()"
"): ng:///AppModule/AnalysisItemComponent.html@89:14
Can't bind to 'colour' since it isn't a known property of 'ugly-regions'.
1. If 'ugly-regions' is an Angular component and it has 'colour' input, then verify that it is part of this module.
2. If 'ugly-regions' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message.
[etc]

I am guessing this means that my new regions/regions.component.ts needs to be imported somewhere. Grepping around a bit, it looks like that place is app.module.ts in the top-level src/app directory. I go in there, import the RegionsComponent, and include it in the @NgModule declaration further down.

The page now loads, and when I run the "Notes or Regions" output of the test plugin, I get the following meaningless output.

I sit back in satisfaction, revelling in my copy-and-paste powers.

Phase 2 is complete.

[cannam]

Added a region layer helper in Waves UI, using the annotated-segment shape; used it for the regions component.