Update the CHANGES.txt for release 0.7.0
Update the CHANGES.txt for release 0.7.0

laserson/adam,bigdatagenomics/adam,allenday/adam,tomwhite/adam,heuermh/adam,erictu/adam,bigdatagenomics/adam,bigdatagenomics/adam,tomwhite/adam,kcompher/adam,tdanford/adam,kcompher/adam,kcompher/adam,rnpandya/adam,massie/adam,tdanford/adam,FusionWorks/adam,massie/adam,laserson/adam,gazimahmud/adam,gazimahmud/adam,allenday/adam,heuermh/adam,heuermh/adam,laserson/adam,bigdatagenomics/adam,laserson/adam,gazimahmud/adam,FusionWorks/adam,SwathiMystery/adam,erictu/adam,VinACE/adam,kcompher/adam,erictu/adam,tomwhite/adam,rnpandya/adam,FusionWorks/adam,SwathiMystery/adam,allenday/adam,gazimahmud/adam,VinACE/adam,erictu/adam,SwathiMystery/adam,heuermh/adam,tomwhite/adam,FusionWorks/adam,tdanford/adam,massie/adam,tdanford/adam,rnpandya/adam,VinACE/adam,allenday/adam,rnpandya/adam,VinACE/adam,SwathiMystery/adam,massie/adam