Merge pull request #220 from luzpaz/therefor

Add therefor->therefore, therefor,
diff --git a/codespell_lib/data/dictionary.txt b/codespell_lib/data/dictionary.txt
index 7604dfc..10acd14 100644
--- a/codespell_lib/data/dictionary.txt
+++ b/codespell_lib/data/dictionary.txt
@@ -4961,6 +4961,7 @@
 ther->there, their, the, other,
 therafter->thereafter
 therby->thereby
+therefor->therefore, therefor,
 therfore->therefore
 theri->their
 theshold->threshold