[FIX] Rename jade to pug

[paradite]

Hi, initially I cloned this repo because I wanted to fix a UI bug in the released version where the title for the note is not shown, and instead the word title is shown. Then I realized that this bug was already fixed in dev branch and dev branch is way ahead of master.

But I found another bug during the setup, that is caused by the renaming of jade into pug in the prismjs package since 1.8.2:

• https://github.com/PrismJS/prism/pull/1201
• https://github.com/PrismJS/prism/blob/gh-pages/CHANGELOG.md#182-2017-10-19

This bug causes the web app to throw error and stop working due to missing dependency:

Error: Cannot find module './prism-jade.min.js'.

Ideally the change should not affect this project because the version of the prismjs package is defined as 1.7.0 in package-lock.json, but somehow 1.7.0 in package-lock.json does not match package.json which is "prismjs": "^1.8.1". So when I did npm install, it fetches prismjs:1.8.4 and updates package-lock.json. Maybe you can regenerate the package-lock.json file? I've checked out package-lock.json in this PR.

FYI: npm's behavior regarding conflicting versions:

• https://stackoverflow.com/a/45566871/1472186
• https://github.com/npm/npm/issues/17979#issuecomment-332701215

[coveralls]

Coverage increased (+10.7%) to 94.905% when pulling 40973ad7198cd0478c700bdcbc880e761a32556d on paradite:dev into 32a569d2210d7e3ecc773de244bac9927867a23a on Laverna:dev.