Update copyright notice in LICENSE.txt
Update copyright notice in LICENSE.txt

Clarify that copyright is not entirely owned by MIT CSAIL, but is instead still assigned to the contributors or their institutions (including MIT CSAIL).
myrtleTree33/Halide,jiawen/Halide,smxlong/Halide,fengzhyuan/Halide,delcypher/Halide,ronen/Halide,rodrigob/Halide,ayanazmat/Halide,dougkwan/Halide,kenkuang1213/Halide,dan-tull/Halide,jiawen/Halide,delcypher/Halide,delcypher/Halide,kgnk/Halide,damienfir/Halide,aam/Halide,psuriana/Halide,dougkwan/Halide,lglucin/Halide,smxlong/Halide,aam/Halide,kgnk/Halide,kenkuang1213/Halide,gchauras/Halide,damienfir/Halide,damienfir/Halide,kenkuang1213/Halide,ronen/Halide,dan-tull/Halide,rodrigob/Halide,mcanthony/Halide,ayanazmat/Halide,gchauras/Halide,jiawen/Halide,rodrigob/Halide,ayanazmat/Halide,delcypher/Halide,kenkuang1213/Halide,delcypher/Halide,myrtleTree33/Halide,myrtleTree33/Halide,dan-tull/Halide,mcanthony/Halide,kenkuang1213/Halide,aam/Halide,ronen/Halide,rodrigob/Halide,dan-tull/Halide,myrtleTree33/Halide,fengzhyuan/Halide,psuriana/Halide,smxlong/Halide,gchauras/Halide,gchauras/Halide,kgnk/Halide,tdenniston/Halide,aam/Halide,gchauras/Halide,kgnk/Halide,damienfir/Halide,tdenniston/Halide,dan-tull/Halide,damienfir/Halide,smxlong/Halide,adasworks/Halide,delcypher/Halide,fengzhyuan/Halide,ayanazmat/Halide,fengzhyuan/Halide,delcypher/Halide,damienfir/Halide,kenkuang1213/Halide,myrtleTree33/Halide,mcanthony/Halide,adasworks/Halide,lglucin/Halide,jiawen/Halide,gchauras/Halide,psuriana/Halide,dan-tull/Halide,smxlong/Halide,lglucin/Halide,rodrigob/Halide,ronen/Halide,mcanthony/Halide,tdenniston/Halide,mcanthony/Halide,lglucin/Halide,aam/Halide,dougkwan/Halide,delcypher/Halide,jiawen/Halide,jiawen/Halide,kenkuang1213/Halide,tdenniston/Halide,smxlong/Halide,psuriana/Halide,dougkwan/Halide,psuriana/Halide,damienfir/Halide,fengzhyuan/Halide,smxlong/Halide,myrtleTree33/Halide,lglucin/Halide,fengzhyuan/Halide,tdenniston/Halide,kgnk/Halide,ayanazmat/Halide,adasworks/Halide,dan-tull/Halide,dougkwan/Halide,aam/Halide,ronen/Halide,ayanazmat/Halide,adasworks/Halide,psuriana/Halide,adasworks/Halide,tdenniston/Halide,mcanthony/Halide,smxlong/Halide,myrtleTree33/Halide,damienfir/Halide,mcanthony/Halide,lglucin/Halide,myrtleTree33/Halide,mcanthony/Halide,rodrigob/Halide,rodrigob/Halide,rodrigob/Halide,ronen/Halide,kgnk/Halide,lglucin/Halide,tdenniston/Halide,dougkwan/Halide,jiawen/Halide,kenkuang1213/Halide,ayanazmat/Halide,fengzhyuan/Halide,aam/Halide,fengzhyuan/Halide,ayanazmat/Halide,psuriana/Halide,kgnk/Halide,adasworks/Halide,adasworks/Halide,dan-tull/Halide,dougkwan/Halide,ronen/Halide,ronen/Halide,tdenniston/Halide,adasworks/Halide,dougkwan/Halide,kgnk/Halide