Added JMeter parser

Hi Bruno,

From Jenkins->Testlink-plugin  https://wiki.jenkins-ci.org/display/JENKINS/Integrating+TestLink++Jenkins++JMeter

I tried to use the shell script to convert the xml from jMeter result but some xml gave me problems, so I decided to parse it directly from java.

I have more changes in the /testlink-plugin pending to push.

Also I had some problems with the encoding, this is the reason why of the change in TapProducerFactory

See you,
Sergio