change Linked assets to return dependent Assets rather than SourceModules
create XMLIdExtractorTest
create XMLAsset that returns list of provided require paths
get dependent LinkedAssets working
fix oredering problem in test
remove some printlns
add spec tests for xml dependencies
fix tests after merge
Linked asstes return dependent Assets rather than LinkedAsset collections
rename variable
Removed all unused imports.
Switched from having two methods to get the available require
paths for an asset (SourceModule.getRequirePath() &
LinkedAsset.getProvidedRequirePaths()) to having only one
(Asset.getRequirePaths()), plus some tidy ups along the way.
Stopped keying linked-assets against the asset-path, and started keying
against the require-path instead.
Renamed badly named variable.
Merge branch 'develop' into dependent-assets

Conflicts:
	brjs-core/src/main/java/org/bladerunnerjs/model/BundlableNode.java
	brjs-core/src/main/java/org/bladerunnerjs/plugin/plugins/bundlers/commonjs/CommonJsContentPlugin.java
	brjs-core/src/main/java/org/bladerunnerjs/plugin/plugins/bundlers/commonjs/CommonJsSourceModule.java
	brjs-core/src/main/java/org/bladerunnerjs/plugin/plugins/bundlers/namespacedjs/NamespacedJsContentPlugin.java
	brjs-core/src/main/java/org/bladerunnerjs/plugin/plugins/bundlers/namespacedjs/NamespacedJsSourceModule.java
	brjs-core/src/main/java/org/bladerunnerjs/plugin/plugins/bundlers/thirdparty/ThirdpartyContentPlugin.java
	brjs-core/src/main/java/org/bladerunnerjs/plugin/plugins/bundlers/thirdparty/ThirdpartySourceModule.java
	brjs-core/src/main/java/org/bladerunnerjs/testing/specutility/AssetContainerVerifier.java
Merge pull request #685 from BladeRunnerJS/dependent-assets

allowing XML config only blades (refactor dependant assets)