Added build.xml and added the dist directory to gitignore

library/.gitignore

@@ -4,3 +4,4 @@ local.properties
 .idea/
 lint.xml
 /.apt_generated
+/dist

library/build.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project name="BluetoothLeLibrary" default="default">
+    <loadproperties srcFile="local.properties" />
+    <property file="ant.properties" />
+    <loadproperties srcFile="project.properties" />
+
+    <!-- quick check on sdk.dir -->
+    <fail message="sdk.dir is missing. Make sure to generate local.properties using 'android update project'" unless="sdk.dir" />
+    
+    <!-- version-tag: 1 -->
+    <import file="${sdk.dir}/tools/ant/build.xml" />
+
+    <!-- Read the Android Manifest -->
+    <path id="android.antlibs">
+        <pathelement path="${sdk.dir}/tools/lib/ant-tasks.jar" />
+    </path>
+
+    <taskdef name="xpath" classname="com.android.ant.XPathTask" classpathref="android.antlibs" />
+    <xpath input="./AndroidManifest.xml" expression="/manifest/@android:versionName" output="manifest.versionName" />
+    
+    <!-- Setup the build properties -->
+    <property name="versionedName" value="${ant.project.name}-${manifest.versionName}" />
+    <property name="distLocation" location="dist" />
+    <echo message="Running task(s) for ${versionedName}" />
+
+    <target name="default">
+      <antcall target="jar"/>
+      <antcall target="doc"/>
+    </target>
+
+    <target name="jar" depends="debug" description="build the library as a jar">
+        <jar destfile="${distLocation}/${versionedName}.jar" basedir="bin/classes" />
+    </target>
+    <target name="doc" description="generate documentation">
+        <property name="temp" location="temp" />
+        <javadoc sourcepath="${source.dir}" destdir="${temp}" />
+        <jar destfile="${distLocation}/${versionedName}-javadoc.jar" basedir="temp" keepcompression="true" />
+        <delete dir="${temp}" />
+    </target>
+</project>