Added caution notes about the removal of AsseticBundle in 2.8/3.0#5973

Closed

javiereguiluz wants to merge 4 commits intosymfony:2.8from javiereguiluz:add_assetic_warning

+137-7

Commits on Dec 7, 2015

Commits on Dec 9, 2015

Reworded everything
javiereguiluz
committed