Add support for command line ant builds

Executing ant from the command line from the PureDataP5 directory fails:

<pre>
$ ant -buildfile resources/build.xml -propertyfile resources/build.properties 
Buildfile: /Users/xxx/working/puredatap5/PureDataP5/resources/build.xml

init:
     [echo] ------------------------------------------------------------------------------------------------
     [echo]     Building the Processing library PureData 1
     [echo] ------------------------------------------------------------------------------------------------
     [echo] 	src path        /Users/xxx/working/puredatap5/PureDataP5/src
     [echo] 	bin path        /Users/xxx/working/puredatap5/PureDataP5/bin
     [echo] 	classpath.local	/Users/xxx/Documents/workspace/libs
     [echo] 	sketchbook      /Users/xxx/Documents/Processing
     [echo] 	java version    1.6
     [echo] ------------------------------------------------------------------------------------------------
     [echo] 	

library.init:
     [echo] init library ...

library.run:
     [echo] building library ...

generate.structure:
   [delete] Deleting directory /Users/xxx/working/puredatap5/PureDataP5/tmp
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/library
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/examples
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/reference
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/src
     [copy] Copying 2 files to /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/examples
     [copy] Copying 1 file to /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/src
     [copy] Copying 14 files to /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/library

generate.source:

generate.source.win:

generate.source.nix:
     [echo] generating source (mac/linux) ...

parse.file:
     [echo] /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/src/org/puredata/processing/PureData.java

compile:
    [javac] Compiling 1 source file to /Users/xxx/working/puredatap5/PureDataP5/bin

BUILD FAILED
/Users/xxx/working/puredatap5/PureDataP5/resources/build.xml:107: The following error occurred while executing this line:
/Users/xxx/working/puredatap5/PureDataP5/resources/build.xml:141: /Users/xxx/Documents/workspace/libs does not exist.

Total time: 0 seconds
</pre>


It also fails from the resources directory:

<pre>
$ ant
Buildfile: /Users/xxx/working/puredatap5/PureDataP5/resources/build.xml

init:
     [echo] ------------------------------------------------------------------------------------------------
     [echo]     Building the Processing library PureData 1
     [echo] ------------------------------------------------------------------------------------------------
     [echo] 	src path        /Users/xxx/working/puredatap5/PureDataP5/src
     [echo] 	bin path        /Users/xxx/working/puredatap5/PureDataP5/bin
     [echo] 	classpath.local	/Users/xxx/Documents/workspace/libs
     [echo] 	sketchbook      /Users/xxx/Documents/Processing
     [echo] 	java version    1.6
     [echo] ------------------------------------------------------------------------------------------------
     [echo] 	

library.init:
     [echo] init library ...

library.run:
     [echo] building library ...

generate.structure:
   [delete] Deleting directory /Users/xxx/working/puredatap5/PureDataP5/tmp
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/library
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/examples
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/reference
    [mkdir] Created dir: /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/src
     [copy] Copying 2 files to /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/examples
     [copy] Copying 1 file to /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/src
     [copy] Copying 14 files to /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/library

generate.source:

generate.source.win:

generate.source.nix:
     [echo] generating source (mac/linux) ...

parse.file:
     [echo] /Users/xxx/working/puredatap5/PureDataP5/tmp/PureData/src/org/puredata/processing/PureData.java

compile:
    [javac] Compiling 1 source file to /Users/xxx/working/puredatap5/PureDataP5/bin

BUILD FAILED
/Users/xxx/working/puredatap5/PureDataP5/resources/build.xml:107: The following error occurred while executing this line:
/Users/xxx/working/puredatap5/PureDataP5/resources/build.xml:141: /Users/xxx/Documents/workspace/libs does not exist.

Total time: 0 seconds
</pre>


The build should be self-contained, i.e. it should not be looking outside of the working directory for resources, such as Documents/workspace/libs.

Including the Processing core jar in the lib directory is perhaps not the best way to solve the issue, but it makes the build self-contained and reproducible.