Feature request: automatically trim indentation

[DrKGD]

Hi there, first and foremost thanks for the great plugin, I tend to share lots of snippets of code to my university colleagues!

I am kind of interested in an autogobble functionality, don't really know whether is it more appropriate to discuss it there or just ask for it on the silicon binary repository: in doubt I am going to also mention it there.
Aloxaf/silicon#213 (comment)

In case you are wondering what autogobble is (name comes from lstautogobble, a package from LaTeX) , look at the following images

Basically it consists of recalculating the indentation at the start of the line, for each line, thus trims the excess.

[0oAstro]

Done