Mkdocs-ezlinks-plugin

This is a bugfix release.

Issues addressed:
* GH issue 35, `Links between deeply nested subfolders fails.`
Dev Mara-Li reported an issue with wikilinks between deeply nested subfolders failing due to an incorrectly
rendered relative link to the file.

* An unreported Windows usage issue
It's possible this bug existed for quite some time. Basically, on Windows, there was disagreement between the
path separators used at different points in the file mapping and searching process. This unifies it to store
and search for paths only with the `/` delimiter instead of the OS defined separator.

Adds support for Reference Link specification links. For example, `[foo]: /bar "Foo Bar"`.

This is a bugfix release.

Issues addressed:
* GH issue 25, `Absolute links not using http:// or https:// are treated as relative`.
Dev robbcrg (thanks!) reported that links with protocol schemes other than those two should also be treated as
absolute links. The regex will exclude any link from a conformant protocol scheme from being converted using EzLinks.

* GH Issue 27, `Dictionary file cache is not being leveraged`.
An inverted comparison led to the fast file cache lookup never really being exercised. Now, if a filename is unique, it will find it in the fast file cache first, saving a more expensive full trie lookup.

This is a bugfix release. The prior release switched from a dictionary lookup to a prefix trie lookup strategy, which allowed for better disambiguation between links, but is more expensive. The bug was that, even if a link was direct, it would trigger a full trie search. Now, direct links
are checked and returned directly if the file exists.

Additionally, a slight performance improvement was made where, in the case that a filename is unique to the entire site, it will rely on a fast dictionary lookup instead of a trie lookup.

Implement auto-disambiguation and bugfix

* This fixes a bug in the previous search strategy that missed
allowing for local relative links (something like index.md
referring to about.md in the same subdirectory).

* It also adds a bit further auto-disambiguation. By this,
I mean it will attempt to find the _closest_ match in proximity
(with respect to the folder hierarchy). For instance,
if this is the layout:


+ guide/
+ test.md
+ getting_started/
+ index.md
+ tutorials/
- test.md
+ getting_started/
+ index.md
+ more_advanced/
+ index.md

If you placed a link inside `guide/getting_started/index.md`
such as `[Test](test)`, the resulting link has ambiguity, but
in the default case, the `guide/test.md` file is _closer_ than
the `tutorials/test.md`, therefore, it will select that file.

You can still further disambiguate the link if desired, but
this provides a bit more sane defaults.

Adds support for EzLink 'path-component' based disambiguation

This feature switches from using a dictionary to a prefix
trie, caching the files in reverse order (path wise),
which allows for:


+ folder1/
- index.md
+ folder2/
- index.md


You can now link to `folder1/index.md` and `folder2/index.md`, or
`folder1/index` and `folder2/index`. This allows disambiguating
duplicate filenames from separate unique paths.

This works across all link types supported by EzLinks