Removed the AssetContainer.namespace() and AssetLocation.namespace()
methods so that plug-ins don't need to be exposed to the idea of
namespacing when it's not actually necesarry -- the namespace can always
be determined from the require prefix.
Modified the AssetLocation.requirePrefix() method to no longer throw a
RequirePathException unnecesarilly.
Remvoed the AssetPlugin.getTestSourceModules() method, which was no
longer required.
Fixed bug that caused asset location plug-ins that provide linked
assets, to also need to provide the same list as plain assets too.
Removed redundant methods from AssetLocation for locating assets by file
extension.
Renamed a couple of methods in the AssetLocation interface, before
introducing a new method.
Re-order the AssetLocation interface so it reads better.
Added an AssetLocation.sourceModules() method so that the AssetContainer
no longer needs to reach through the AssetLocation, and perform this
work itself.
AssetPlugin now only has a single getAssets(AssetLocation assetLocation)
method -- this will next be changed to getAsset(File file, AssetLocation
assetLocation)
Progress towards AssetPlugin only having a single getAsset() method that
will allow it to deal with a single file at a time only, simplifying
plug-in design by not needing to worry about not creating an asset for
the same file twice, and increasing performance since we don't need to
keep re-iterating the same set of files.
Deleting tests that appear to test behaviour that will no longer be
possible with the new AssetPlugin design.
Moved a method in the inheritance hierarchy so that it's available to
all specializations of AbstractShallowAssetLocation.
AssetPlugin now has a single getAsset() method that only deals with a
single file at a time only.
Rename AbstractShallowAssetLocation to AbstractAssetLocation, as it's
the base for all AssetLocation classes.
Removed scaffolding code from the AssetLocation classes.
Removed final usage of, and the need for, AssetLocation.obtainAsset()
and AssetLocation.obtainMatchingAssets().
Re-organized AbstractAssetLocation to match the order of the method
definitions in AssetLocation.
Tidy-up of AbstractAssetLocation specializations.
Merge branch 'develop' into asset-plugin-simplification

Conflicts:
	brjs-core/src/main/java/org/bladerunnerjs/aliasing/aliasdefinitions/AliasDefinitionsReader.java
	brjs-core/src/main/java/org/bladerunnerjs/model/AbstractShallowAssetLocation.java
Merge pull request #599 from BladeRunnerJS/asset-plugin-simplification

Asset plugin simplification