Re-enable warnings on plugins building

Change-Id: Ia4b0279b0db183c9267c39e9ecc2387d21f5fa11
Reviewed-on: http://gerrit.dmdirc.com/3094
Reviewed-by: Chris Smith <chris@dmdirc.com>
Automatic-Compile: DMDirc Build Manager

build.xml

@@ -53,7 +53,13 @@
     <target name="compile" depends="-init-compile">
        <javac srcdir="${plugins.src}" destdir="${plugins.build.classes}"
               classpathref="plugins.classpath" includeantruntime="false"
-              debug="true"/>
+              debug="true" deprecation="true">
+           <compilerarg value="-Xlint:all"/>
+           <compilerarg value="-Xmaxwarns"/>
+           <compilerarg value="1000"/>
+           <compilerarg value="-Xmaxerrs"/>
+           <compilerarg value="1000"/>
+       </javac>
 
        <copy todir="${plugins.build.classes}">
           <fileset dir="${plugins.src}">