Revised introduction
Revised introduction

Please someone @mariosky or @fergunet have a look at the line of argument to see if it's OK.

Ref #20

geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN,geneura-papers/2016-ea-languages-PPSN