Metakernel

- Escape backslashes in strings [226](https://github.com/Calysto/metakernel/pull/226) ([ellert](https://github.com/ellert))
- Add missing dollar signs to %latex examples and tests [225](https://github.com/Calysto/metakernel/pull/225) ([ellert](https://github.com/ellert))
- Support older jedi versions [224](https://github.com/Calysto/metakernel/pull/224) ([ellert](https://github.com/ellert))

- Add support for `SOURCE_DATE_EPOCH` [223](https://github.com/Calysto/metakernel/pull/223) ([jnahmias](https://github.com/jnahmias))

- Fix warnings when running tests under python 3.9 [222](https://github.com/Calysto/metakernel/pull/222) ([jnahmias](https://github.com/jnahmias))

- Use `TERM=dumb` for bash `REPLWrapper` [221](https://github.com/Calysto/metakernel/pull/221) ([jnahmias](https://github.com/jnahmias))
- Use `tempfile` instead of writing to `cwd` [220](https://github.com/Calysto/metakernel/pull/220) ([jnahmias](https://github.com/jnahmias))

- More `py2` removal [219](https://github.com/Calysto/metakernel/pull/219) ([blink1073](https://github.com/blink1073))
- Remove `py2` [218](https://github.com/Calysto/metakernel/pull/218) ([joequant](https://github.com/joequant))
- Monkey patch display to output to kernel [216](https://github.com/Calysto/metakernel/pull/216) ([joequant](https://github.com/joequant))
- Fix warnings [215](https://github.com/Calysto/metakernel/pull/215) ([joequant](https://github.com/joequant))

- Dev/fix `retval` in `exec` [214](https://github.com/Calysto/metakernel/pull/214) ([joequant](https://github.com/joequant))