Add Spring third party repository for Adobe Blaze artifacts

Hi!

Thanks for lapdftext, I used it in a news PDF, and it worked quite well. I'll continue working on the resulting XML blocks to produce some useful text and continue with the rest of my analysis. 

I noticed there was a commented repo for BlazeDS artifacts. Maybe the Spring 3rd Party repo sounds more reliable? I used the link found in this JIRA comment: https://jira.spring.io/browse/FLEX-216

Packaging the JAR and running following the instructions results in one of those incompatible Java version messages (Unsupported major.minor version 51.0). In my case I needed to downgrade the Java target version from 1.7 to 1.6, since the bin scripts were locked in JVM 1.6, and complained if I used the 1.7 openjdk. My env:

Apache Maven 3.2.1 (ea8b2b07643dbb1b84b6d16e1f08391b666bc1e9; 2014-02-14T15:37:52-03:00)
Maven home: /opt/apache-maven-3.2.1
Java version: 1.8.0_05, vendor: Oracle Corporation
Java home: /opt/jdk1.8.0_05/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "3.13.0-32-generic", arch: "i386", family: "unix"