Fix footnote parsing
Fix footnote parsing

Consecutive footnotes do not need to be surrounded by blank lines,
courtesy of @microjo. For example, this is now possible:

[^1]: footnote1
[^2]: footnote2

kaneshin/redcarpet,gitcafe-dev/redcarpet,vmg/redcarpet,JuanitoFatas/redcarpet,fukayatsu/redcarpet,be9/redcarpet,increments/greenmat,fukayatsu/redcarpet,Hacker0x01/redcarpet,JuanitoFatas/redcarpet,increments/greenmat,liquorburn/redcarpet,be9/redcarpet,kattybilly/redcarpet,emq/redcarpet,liquorburn/redcarpet,vmg/redcarpet,be9/redcarpet,kattybilly/redcarpet,gitcafe-dev/redcarpet,kaneshin/redcarpet,emq/redcarpet,liquorburn/redcarpet,increments/greenmat,JuanitoFatas/redcarpet,be9/redcarpet,emq/redcarpet,Hacker0x01/redcarpet,vmg/redcarpet,emq/redcarpet,vmg/redcarpet,fukayatsu/redcarpet,kaneshin/redcarpet,fukayatsu/redcarpet,increments/greenmat,kattybilly/redcarpet,Hacker0x01/redcarpet,kaneshin/redcarpet,Hacker0x01/redcarpet,gitcafe-dev/redcarpet,liquorburn/redcarpet,kattybilly/redcarpet