README: explain the name dex
README: explain the name dex

People are going to ask, might as well get it out there.

oren/dex,no2key/dex,deliangyang/dex,dullgiulio/dex,joeatwork/dex,mequanta/dex,zlabjp/dex,bcwaldon/dex,no2key/dex,deliangyang/dex,no2key/dex,sercand/dex,bcwaldon/dex,cpswan/dex,jhuntoo/dex,oren/dex,Amirus/dex,ivankravchenko/dex,oren/dex,ecnahc515/dex,Amirus/dex,mequanta/dex,andrewstuart/dex,joeatwork/dex,derekparker/dex,Tecsisa/dex,yifan-gu/dex,Amirus/dex,joeatwork/dex,jhuntoo/dex,shaunstanislaus/dex,philhug/dex,sercand/dex,Tecsisa/dex,ivankravchenko/dex,alihalabyah/dex,derekparker/dex,bcwaldon/dex,Tecsisa/dex,deliangyang/dex,alihalabyah/dex,ecnahc515/dex,ivankravchenko/dex,cpswan/dex,yifan-gu/dex,andrewstuart/dex,zlabjp/dex,ecnahc515/dex,philhug/dex,andrewstuart/dex,shaunstanislaus/dex,dullgiulio/dex,yifan-gu/dex,shaunstanislaus/dex,bobbyrullo/dex,jhuntoo/dex,bobbyrullo/dex,mequanta/dex,zlabjp/dex,cpswan/dex,derekparker/dex,philhug/dex,bobbyrullo/dex,alihalabyah/dex,dullgiulio/dex,sercand/dex