Tweak debug logging

[karlseguin]

1 - Add a log_level build option to control the default log level from
the build (e.g. -Dlog_level=debug). Defaults to info

2 - Add a new boolean log_unknown_properties build option to enable
logging unknown properties. Defautls to false.

3 - Remove the log debug for script eval - this can be a huge value
(i.e. hundreds of KB), which makes the debug log unusable IMO.

[sjorsdonkers]

What about defaulting to .debug if build.mode == debug?

[karlseguin]

I find the noise to signal ratio is too low right now. The point of the flag is to let everyone set it to whatever they want, without having to touch the source. So the default can be anything.

[krichprollsch]

What about adding a make run-debug command to active -Dlog_level=debug and -Dlog_unknown_properties=true?

EDIT: maybe it's make build-dev we should update since it's a "Build in debug mode"?

[karlseguin]

Well, you were right...depending on the page, -Dlog_unknown_properties=true can be a bit overwhelming. It might be better with the incoming CSS stuff, but right now, I think it's only useful as a one-off in really mysterious situations.

But I'll add a make run-debug and change make build-dev to add the -Dlog_level=debug then have 2 debug commands that we can tweak the parameters for as things progress.