Accidentally, I have pushed the .pyc files to the master repository. Now I want to delete them but I can´t do it. Is there any way to remove them directly from the Bitbucket sit
No, you cannot delete them directly from the BitBucket interface but you can delete them in your local checkout and find ./ -type f -name '*.pyc' -exec git rm {} \; ( or simply git rm each pyc file one by one ). Then commit/push your changes.
Finally, to avoid ever making the same mistake again you may create a file at the root of your repo and name it '.gitignore' with the contents:
*.pyc
*~
*.swp
*~ and ~.swp are other commonly forgotten file types that are often accidentally pushed. See the github doc on gitignore https://help.github.com/articles/ignoring-files (and their repo of .gitignore files for some nice defaults).