Use params.sections (if present) for sections

[olehermanse]

This will add a second nav bar under site name,
with entries from params.sections.

If you don't add these params, generated markup will be exactly like before

Example:

[params.sections]
"/" = "~/"
"/posts" = "Posts"
"/projects" = "Projects"

[olehermanse]

Fixes #22

[ribice]

My site still uses Hemingway theme (forked one), and I apply changes there after pushing them Kiss. I'll migrate my blog in few following days and test your changes.

[olehermanse]

@ribice cool, thanks. My site is live, running my fork with these changes: https://www.oleherman.com/

[ribice]

@olehermanse Can you update the readme and exampleSite for these changes? Thanks!

[olehermanse]

I see @mateimicu has updated this and also README, thanks!

@ribice You should consider using merge instead of squash in GitHub UI (unless commit history is messy). This PR had 3 commits, one which was written by @mateimicu , and 1 change to css link (which isn't really related to params.sections). You "destroy" this history by squashing it into 1 commit. (It is also nicer in a lot of other subtle ways, like preserving hashes, gpg signatures and makes git rebase work better).

[ribice]

@olehermanse Haven't thought of that. Generally I squash my own commits since I make plenty of them while working on a single feature. Will make merge commits from now on. Sorry.

[olehermanse]

@ribice no worries. Squashing makes sense sometimes, but not always :)