Fix typos discovered by codespell (#226)

* Fix typos discovered by codespell

* Revert changes to CI

devtools/travis-ci/push-docs-to-s3.py

@@ -21,7 +21,7 @@ else:
     PREFIX = thermopyl.version.short_version
 
 if not any(d.project_name == 's3cmd' for d in pip.get_installed_distributions()):
-    raise ImportError('The s3cmd pacakge is required. try $ pip install s3cmd')
+    raise ImportError('The s3cmd package is required. try $ pip install s3cmd')
 # The secret key is available as a secure environment variable
 # on travis-ci to push the build documentation to Amazon S3.
 with tempfile.NamedTemporaryFile('w') as f:

pdbfixer/pdbfixer.py

@@ -742,7 +742,7 @@ class PDBFixer(object):
         -----
 
         We require three letter codes to avoid possible ambiguitities.
-        We can't guarnatee that the resulting model is a good one; for
+        We can't guarantee that the resulting model is a good one; for
         significant changes in sequence, you should probably be using
         a standalone homology modelling tool.