Logging vs Reporting

[Christopher James Halse Rogers]

Hey all.

This is somewhat of a revival of a discussion from London, and 
tangentially related to the contentious fatal-error branch.

We currently have no logging in our codebase outside of the 3rd_party 
android code. This makes it difficult to work out what's happening when 
things go wrong because we get nothing but a “oops, this didn't 
work” exception without context; hence the fatal-error branch.

I remember there was some resistance to freeform logging in London. 
What do people think about a global mir::log(mir_severity¹ severity, 
char const* format, ...) function for freeform logging, with this going 
out to the console by default?

¹: Suggested severities - {debug, info, warning, error}