Added $_SERVER['USER'] as possible value for <vendor> part of package name.
Added $_SERVER['USER'] as possible value for <vendor> part of package name.

vdm-io/composer,nicolas-grekas/composer,pierredup/composer,stof/composer,composer/composer,floverdevel/composer,fabpot/composer,slbmeh/composer,stefangr/composer,localheinz/composer,erasys/composer,naderman/composer,johnstevenson/composer,andrerom/composer,milleruk/composer,SpacePossum/composer,gencer/composer,staabm/composer,dzuelke/composer,alcohol/composer