* Fix encodebase64 and decodebase64 filters
The documentation for encodebase64 says that the input is treated as
binary data, but in fact the input is being treated as text data, with
an extra UTF-8 encoding step being performed first.
Likewise, the decodebase64 documentation says that it outputs binary
data, but in fact it will do a UTF-8 decoding step before producing
output, which will in fact garble binary data.
This commit changes the behavior of encodebase64 and decodebase64 to
match what the documentation says they do. It also adds an optional
`text` suffix to both filters to keep the current behavior.
Finally, an optional `urlsafe` suffix is added to both filters to allow
them to use the "URL-safe" variant of base64 (using `-` instead of `+`
and `_` instead of `/`).
* Try to fix failing test
Turns out a little more than this is going to be needed.
* Fix binary base64 encoding, including unit tests
* Update base64 filter documentation
* Can't use replaceAll, too new
Have to use String.replace with a global regex instead
* Replace uses of window.btoa() in rest of code
Since window.btoa() is not available under Node.js, we'll replace all
uses of it with the $tw.utils.base64encode() function that now works
correctly for binary data.
* Add link to UTF-8 glossary definition at MDN
326ae61929