Gateway: add new services: Console, IO, Text
Add utility classes, migrated from ImageJ core

Migrated from:
https://github.com/imagej/imagej/tree/imagej-2.0.0-beta-7.9/core/core/src/main/java/imagej/util
Add non-image-specific services from ImageJ core

This includes the module and command frameworks, including widgets
(module preprocessing that handles inputs) and displays (module
postprocessing that handles outputs).

It also includes the menu, options, platform, script and tool services.

Migrated from:
https://github.com/imagej/imagej/tree/imagej-2.0.0-beta-7.9/core/core/src/main/java/imagej
ContextCreationTest: expect new services, too
Remove imagej-isms from javadoc
SciJavaPlugin: add core plugin type descriptions

This was migrated from the javadoc of ImageJ's ImageJPlugin.
Add new services to the gateway
Migrate RecentFileService from ImageJ

Migrated from:
https://github.com/imagej/imagej/tree/imagej-2.0.0-beta-7.9/core/core/src/main/java/imagej/io
Add icons used by the module and script frameworks

Migrated from:
https://github.com/imagej/imagej/tree/imagej-2.0.0-beta-7.9/core/core/src/main/resources/icons
ContextCreationTest: add RecentFileService
Merge branch 'mega-split'

This branch migrates many non-image-specific services from the ImageJ
core component.

This includes the module and command frameworks, including widgets
(module preprocessing that handles inputs) and displays (module
postprocessing that handles outputs).

It also includes the menu, options, platform, script and tool services.

Migrated from:
https://github.com/imagej/imagej/tree/imagej-2.0.0-beta-7.9/core/core/src/main/java/imagej
POM: bump to pom-scijava 1.160
POM: organize dependencies
POM: remove obsolete comment
POM: tidy up the order of configuration blocks

This was done using:
    mvn tidy:pom
Merge remote-tracking branch 'origin/master'