This change ignores templatedir for css files.
It assumes that the paths in the stylesheets
variable are relative to the qdocconf file that
contains the stylesheets variable.

Task-number: QTBUG-27878
Change-Id: I2155e58f352e17d710c93ad4e92679beb169d823
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>