Update INSTALL

Refined install manual, some important details were not clearly stated.
fixed #69
Merge pull request #70 from tothfn/69

fixed #69
Updated the xml parsing according to the changes in sif
Merge remote-tracking branch 'upstream/master'
Reverted the change from attributes to elements
Merge pull request #71 from krauswg/master

Processing of the jaxb created findings
Merge branch 'master' of github.com:kuleszdl/SIFEI