Log Message:
py-nbconvert: updated to 5.4.0

5.4.0:

New Features
- No input flag (--no-input)
- Add alias --to ipynb for notebook exporter
- Add export_from_notebook
- If set, use nb.metadata.authors for LaTeX author line
- Populate language_info metadata when executing
- Support for \mathscr
- Allow the execute preprocessor to make use of an existing kernel
- Refactor ExecutePreprocessor
- Update widgets CDN for ipywidgets 7 w/fallback
- Add support for adding custom exporters to the "Download as" menu.
- Enable ANSI underline and inverse
- Update notebook css to 5.4.0
- Change default for slides to direct to the reveal cdn rather than locally
- Use "title" instead of "name" for metadata to match the \ 
notebook format
- Img filename metadata
- Added MathJax compatibility definitions
- Per cell exception
- Simple API for in-memory templates
- Set BIBINPUTS and BSTINPUTS environment variables when making PDF
- If nb.metadata.title is set, default to that for notebook

Deprecations
- Drop support for python 3.3

Fixing Problems
- Fix api break
- Don't remove empty cells by default
- Handle attached images in html converter
- No need to check for the channels already running
- Update font-awesome version for slides
- Properly treat JSON data
- Skip executing empty code cells
- Ppdate log.warn (deprecated) to log.warning
- Cleanup notebook.tex during PDF generation
- Windows unicode error fixed, nosetest added to setup.py
- Better content hiding; template & testing improvements
- Fix Jinja syntax in custom template example.
- Fix for an issue with empty math block
- Add parser for Multiline math for LaTeX blocks
- Use defusedxml to parse potentially untrusted XML
- Fixes for traitlets 4.1 deprecation warnings

Testing, Docs, and Builds
- A couple of typos
- Add python_requires metadata.
- Document --inplace command line flag.
- Fix minor typo in usage.rst
- Add note about local reveal_url_prefix
- Move onlyif_cmds_exist decorator to test-specific utils
- Include LICENSE file in wheels
- Added Ubuntu Linux Instructions
- Check for too recent of pandoc version
- Removing more nose remnants via dependencies.
- Remove offline statement and add some clarifications in slides docs
- Linkify PR number
- Added shebang for python
- Upgrade mistune dependency
- add feature to improve docs by having links to prs
- Update notebook CSS from version 4.3.0 to 5.1.0
- Explicitly exclude or include all files in Manifest.