Skip FontName vs. BaseFont check for Type 3 fonts

Type 3 font dict does not have a BaseFont entry (see PDF Reference 9.6.5 Table 112). This check is actually causing false positives:
http://math.berkeley.edu/~daisuke/Bonn2013.pdf
http://math.berkeley.edu/~daisuke/BVSOL.pdf
http://www.ieice-hbkb.org/files/06/06gun_02hen_04.pdf
http://www.asahi-net.or.jp/~td6i-st/fuku-cathedral/new/gat.pdf