Make ANTLR 4 runtime maven artifacts OSGi-ready

Added maven-bundle-plugin + metadata configuration to antlr4-runtime and
antlr4-annotations jar manifests to allow antlr4 runtime to be used to
execute parsers in OSGi runtime.

The addition of OSGi metadata as generated by the maven-bundle-plugin (actually it is generated by a tool called [Bnd](http://www.aqute.biz/Code/Bnd)  which is invoked by the plugin) adds to the manifest of *antlr4-runtime* and *antlr4-annotations* manifests as follows (standard jar manifest entries remain and are highlighted in bold):

Firstly antlr4-runtime:

__Manifest-Version: 1.0__
Bnd-LastModified: 1409190229833
__Build-Jdk: 1.7.0_25__
__Built-By: cd01__
Bundle-Description: The ANTLR 4 Runtime
Bundle-DocURL: http://www.antlr.org
Bundle-License: http://www.antlr.org/license.html
Bundle-ManifestVersion: 2
Bundle-Name: ANTLR 4 Runtime
Bundle-SymbolicName: org.antlr.antlr4-runtime
Bundle-Vendor: ANTLR
Bundle-Version: 4.4.0.SNAPSHOT
__Created-By: Apache Maven Bundle Plugin__
Export-Package: org.antlr.v4.runtime;uses:="org.antlr.v4.runtime.dfa,org
 .antlr.v4.runtime.atn,org.antlr.v4.runtime.misc,org.antlr.v4.runtime.tr
 ee,org.antlr.v4.runtime.tree.pattern,org.antlr.v4.runtime.tree.gui,java
 x.print,javax.swing";version="4.4.0.SNAPSHOT",org.antlr.v4.runtime.tree
 .gui;uses:="org.antlr.v4.runtime.tree,org.abego.treelayout,org.antlr.v4
 .runtime.misc,org.abego.treelayout.util,javax.swing,javax.swing.event,j
 avax.swing.tree,javax.swing.filechooser,javax.swing.border,javax.print,
 javax.imageio";version="4.4.0.SNAPSHOT",org.antlr.v4.runtime.tree.xpath
 ;uses:="org.antlr.v4.runtime,org.antlr.v4.runtime.tree,org.antlr.v4.run
 time.dfa,org.antlr.v4.runtime.atn";version="4.4.0.SNAPSHOT",org.antlr.v
 4.runtime.dfa;uses:="org.antlr.v4.runtime.atn,org.antlr.v4.runtime.misc
 ";version="4.4.0.SNAPSHOT",org.antlr.v4.runtime.atn;uses:="org.antlr.v4
 .runtime,org.antlr.v4.runtime.misc,org.antlr.v4.runtime.dfa";version="4
 .4.0.SNAPSHOT",org.antlr.v4.runtime.tree.pattern;uses:="org.antlr.v4.ru
 ntime.misc,org.antlr.v4.runtime.tree,org.antlr.v4.runtime,org.antlr.v4.
 runtime.tree.xpath,org.antlr.v4.runtime.atn";version="4.4.0.SNAPSHOT",o
 rg.antlr.v4.runtime.misc;uses:="javax.swing,javax.imageio,javax.print,j
 avax.print.attribute,org.antlr.v4.runtime,org.antlr.v4.runtime.atn";ver
 sion="4.4.0.SNAPSHOT",org.antlr.v4.runtime.tree;uses:="org.antlr.v4.run
 time,org.antlr.v4.runtime.misc,org.antlr.v4.runtime.tree.gui";version="
 4.4.0.SNAPSHOT"
__Implementation-Title: ANTLR 4 Runtime__
__Implementation-Vendor: ANTLR__
__Implementation-Vendor-Id: org.antlr__
__Implementation-Version: 4.4-SNAPSHOT__
Import-Package: javax.imageio,javax.print,javax.print.attribute,javax.sw
 ing,javax.swing.border,javax.swing.event,javax.swing.filechooser,javax.
 swing.tree,org.abego.treelayout,org.abego.treelayout.util
Tool: Bnd-1.50.0

and secondly antlr4-annotations:

__Manifest-Version: 1.0__
Bnd-LastModified: 1409178802662
__Build-Jdk: 1.7.0_25__
__Built-By: cd01__
Bundle-Description: A set of annotations used within the ANTLR 4 Runtime
Bundle-DocURL: http://www.antlr.org
Bundle-License: http://www.antlr.org/license.html
Bundle-ManifestVersion: 2
Bundle-Name: ANTLR 4 Runtime Annotations
Bundle-SymbolicName: org.antlr.antlr4-annotations
Bundle-Vendor: ANTLR
Bundle-Version: 4.4.0.SNAPSHOT
__Created-By: Apache Maven Bundle Plugin__
Export-Package: org.antlr.v4.runtime.misc;uses:="javax.lang.model.elemen
 t,javax.lang.model.util,javax.tools,javax.lang.model,javax.lang.model.t
 ype,javax.annotation.processing";version="4.4.0.SNAPSHOT"
Fragment-Host: org.antlr.antlr4-runtime
__Implementation-Title: ANTLR 4 Runtime Annotations__
__Implementation-Vendor: ANTLR__
__Implementation-Vendor-Id: org.antlr__
__Implementation-Version: 4.4-SNAPSHOT__
Import-Package: javax.annotation.processing,javax.lang.model,javax.lang.
 model.element,javax.lang.model.type,javax.lang.model.util,javax.tools
Tool: Bnd-1.50.0

*ok, there is a slight difference in that with maven jar plugin you will get **Archiver-Version: Plexus Archiver*** :wink:
Is there a reason to change this from the default location (`${project.build.outputDirectory}/META-INF`)? For reference:

| Expression | Value |
| --- | --- |
| `${project.build.outputDirectory}/META-INF` | **target/classes/META-INF** |
| `${project.build.directory}/META-INF` | **target/META-INF** |