[Qgis-psc] Scrutinizer testing now enabled

[Nyall Dawson]

Hey all,

Following up the recent launch of CI testing under OSX, Tim has now
enabled Scrutinizer checks on the QGIS master branch.
What this means is that now every commit & PR is tested by
Scrutinizer's checker. This checks for bugs and bad practices in
Python code and will alert us of any potential issues prior to merging
PRs. You can see the results of each check at the bottom of recent PRs
- you should see both the results of this check and Travis' Linux/OSX
testing.

It'll be interesting to see how useful this is in the long run, but in
any case it's a free service (for open source projects) and doesn't
require any extra infrastructure on our behalf. Hopefully it's an easy
win and is able to prevent some Python errors slipping in to the code
in future....

Nyall