Improve console implementation

Rewrite console improvements (console colors, tab completion,
persistent input line, ...) using JLine 3.x and TerminalConsoleAppender.

New features:
  - Support console colors for Vanilla commands
  - Add console colors for warnings and errors
  - Server can now be turned off safely using CTRL + C. JLine catches
    the signal and the implementation shuts down the server cleanly.
  - Support console colors and persistent input line when running in
    IntelliJ IDEA

Other changes:
  - Update JLine to 3.3.1 (from 2.12.1)
  - Server starts 1-2 seconds faster thanks to optimizations in Log4j
    configuration

pom.xml

@@ -40,6 +40,11 @@
             <id>aikar</id>
             <url>http://ci.emc.gs/nexus/content/groups/aikar/</url>
         </repository>
+        <repository>
+            <!-- TODO: Remove when TerminalConsoleAppender is released -->
+            <id>oss-snapshots</id>
+            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
+        </repository>
     </repositories>
 
     <distributionManagement>