2.0.0-25 is released - java 11 support is mainlined

[seth/nqzero]

2.0.0-25 is released, which includes the java 11 support that was previously in a separate `-jdk11` version. this version supports java 8, 9 and 11

    <dependency>
        <groupId>org.db4j</groupId>
        <artifactId>kilim</artifactId>
        <version>2.0.0-25</version>
    </dependency>

https://github.com/nqzero/kilim

other variants:

• `2.0.0-25-jdk7` supports java 7 (java 7 lacks default methods, which are used to support SAMs, so this needs to be distinct)
• `2.0.0-25-jdk10` supports java 10 (a bug in java 10 refuses to run valid bytecode - this is expected to be fixed on oct 16 with the release of java 10.3)

in addition to the mainlining of java 11 support, a few minor bug fixes:

• java 11 support
• `Task.idledown()` no longer starts a scheduler (if one isn't already running) just to immediately stop it
• runtime weaver delegates to the system classloader before attempting to weave (previously used a regex to filter jdk.*, com.sun.*, java.* and javax.* namespaces (some of which technically can be used for user-space packages)
• github includes a new JShell demo - run Pausable code in the REPL