Introducing JavaScript Extension

[MRHMisu]

This pull request introduces JavaScript Extension for Siamese. The extension has been developed following the Siamese Language Extension Manual provided by @tsuiwwwayne.

Four Interfaces are implemented with some additional classes. Implemented Interfaces for JavaScript can be found under the package crest.siamese.language.javascript

• JSNormalizer.java
• JSTokenizer.java
• JSMethodParser.java
• JSNormalizerMode.java

Additional Classes:

• JSParseTreeListener.java
• Builder.java
• ErrorListenerTest.java

Two supportive Classes are required to store inside the crest.siamese.language.javascript.antlr4. These classes are provided with ANTLR4 JavaScript Grammar They will not be generated by ANTLR4; instead, the generated JavaScriptLexer and JavaScriptParser are inherited from these classes.

• JavaScriptLexerBase.java
• JavaScriptParserBase.java

Apart from this, Siamese now can take multiple file extension as input, for example, in the config.properties file:

• extension=js, jsx

For all newly added classes, 38 unit test cases are added. The test suit has achieved almost 100% Line Coverage.

Feel free, to ask any question regarding the JavaScript extension.

[MRHMisu]

@cragkhit Could you please review and approve the pull request?

[MRHMisu]

@cragkhit Thanks for your feedback. The config.properties has been reverted to Java configuration.