fix up wrong offsets of Markdown link label, introduced in PR #7
Revert "Merge pull request #9 from contolini/master"

This reverts commit fc3e4764b3f764ee32cb57f8209090751766d706, reversing
changes made to b79aff28bb480a5283905706a31fc42f29669dbd.
Merge pull request #10 from imcotton/link-label

Fixing Wrong Offsets of Markdown Link Label