Obsidiantools

**New features:**
- Support for canvas files (the latest addition to Obsidian). See the [Canvas files features notebook](https://nbviewer.org/github/mfarragher/obsidiantools-demo/blob/main/Canvas%20file%20features.ipynb) for detail on functionality.
- Nested tags are now supported. By default, `Vault` will not account for nested tags (as has previously been the case).
- Column for `n_tags` in `get_note_metadata` method.
- `get_wikilink_counts` method added.

**Other improvements:**
- `Vault` can handle duplicate filenames, better reflecting the 'Shortest path when possible' wikilink setting in Obsidian.
- More robust regex for tags.
- Fix bug where "tags" were being parsed from code block.
- More error handling for front matter.
- Fix bug where `source_text` gets cut off after a LaTeX block.
- Wikilinks are robust to the use of file extension `md` in them.

Package now requires Python 3.9 as a minimum.

Wiki has now been added to the Github repo, to cover detail for advanced users.

**Bug fixes:**
- Fixed issue where markdown could not parse at all on some environments. `md_mermaid` extension has been removed. This issue was hard to reproduce so I have removed the extension for now.

**New features:**
- The API now has **two forms of text: 'source text' and 'readable text'.** These have their own object attributes and methods, e.g. `get_source_text()` and `get_readable_text()`. The old `text` attributes and objects have been removed, but they were closest to the source text functionality. The readable text is essentially has a lot of formatting removed, while still retaining the context within notes, so it is in a form that can be used quite easily for NLP analysis. The source text best reflects how notes are formatted in the Obsidian app's 'source mode'.
- Applied multiple pymarkdown extensions to the logic, to reflect some of the main features of how Obsidian uses extended markdown. For example, mermaid diagrams, LaTeX equations and tables can now be parsed, tilde characters mark the deletion of text, etc.
- LaTeX equations can now be accessed for notes via `get_math` method and `math_index` attribute.
- More robust tag parsing.

**Bug fixes:**
- More robust paths for cross-platform support.
- Front matter parsing is more robust.

**New features:**
- Support for tags
- Support for instantiating Vault on a filtered list of subdirectories
- 'Gather' functionality for note text: gather function; get_note function and notes_index attr

**Fixes:**
- Fix embedded files output where the pipe operator is used (e.g. to scale images): avoid backslashes appearing in output
- More robust processing of front matter

**New features:**
- Support for front matter
- Support for embedded files
- More columns in metadata df
- get_md_links