Use bulk mode in class name completion (fixes #40)

[derSascha]

Running Java class name completion on large jar files (e.g. Spark, 35MB, 22K Classes) takes long (e.g. Class names with an A takes ~180 Seconds).

Open the jar and seeking to the class on each class takes very long:

RSTALanguageSupport/src/main/java/org/fife/rsta/ac/java/buildpath/JarLibraryInfo.java

Lines 96 to 104 in c4ff0a2

	@Override
	public ClassFile createClassFile(String entryName) throws IOException {
	JarFile jar = new JarFile(jarFile);
	try {
	return createClassFileImpl(jar, entryName);
	} finally {
	jar.close();
	}
	}

Instead of open the jar on every class, use the bulk API on class name completion. This reduce the time in the example above to ~3s.

[derSascha]

@bobbylight what do you think about the PR? Its a very small but very power full fix.

[bobbylight]

Closing in favor of #83. Thanks @derSascha !