reduce some of the install warnings

[chearon]

I've been getting a little tired of all of the warnings when you npm install, so I upgraded the Jade dependency and that gets rid of 2 of them. They renamed Jade to pug, it is a major version update and it's also beta but I could find no issues with the browser tests.

I guess these warnings only show up when you install Canvas directly, but still!

Before

npm WARN deprecated jade@1.11.0: Jade has been renamed to pug, please install the latest version of pug instead of jade
npm WARN deprecated transformers@2.1.0: Deprecated, use jstransformer
npm WARN deprecated jade@0.26.3: Jade has been renamed to pug, please install the latest version of pug instead of jade
npm WARN deprecated to-iso-string@0.0.2: to-iso-string has been deprecated, use @segment/to-iso-string instead.
npm WARN deprecated minimatch@0.3.0: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue

After

npm WARN deprecated jade@0.26.3: Jade has been renamed to pug, please install the latest version of pug instead of jade
npm WARN deprecated to-iso-string@0.0.2: to-iso-string has been deprecated, use @segment/to-iso-string instead.
npm WARN deprecated minimatch@0.3.0: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue

[LinusU]

Thank you, cleanups are highly welcome, you rock!

[chearon]

Haha no problem!