#21 support package-info.java

[vmiazzo]

From Java 1,5 is possible to include package documentation in a file named package-info.java.
See http://java.sun.com/j2se/1.5.0/docs/tooldocs/windows/javadoc.html#packagecomment

Macker 0.4.2 fails when such file is used:
[macker] Unable to parse class file: C:\ws\project\build\my\package\package-info.class
[macker] unable to parse class name / signature: "my.package.package-info" (got "my.package.package-info")