Added expat package 2.1.0

Added expat package, provide PPA packages:

* expat XML parsing C library - example application
* lib64expat1 XML parsing C library - runtime library (64bit)
* lib64expat1-dev XML parsing C library - development kit (64bit)
* libexpat1 XML parsing C library - runtime library
* libexpat1-dev XML parsing C library - development kit
* libexpat1-udeb XML parsing C library - runtime library