Consolidating debugging levels (via Easy Hacks)

[Bjoern Michaelsen]

Hi,

we still have multiple othogonal and confusing debug levels in LibreOffice,
that can interact in funky ways, the most common ones being OSL_DEBUG_LEVEL and
DBG_UTL.

I'd like to propose to consolidate these into _one_ general debug level with no
funky interaction. As such, I'd like to work towards the following (ideally via
Easy Hacks):
- Disable all current code that is enabled by OSL_DEBUG_LEVEL > 1 by enclosing
  them in "#if 0" (or alternatively: triggered by an explicit define for the
  area of code e.g. say DEBUG_SW_LAYOUT)
- Once that is done, make OSL_DEBUG_LEVEL = 2 and DBG_UTL equivalent.

The goal is to have three general debug levels on one axis:
- level 0: release build
- level 1: additional debug code, but binary compatible with level 0 (same
           library interface, comparable to OSL_DEBUG_LEVEL = 1)
- level 2: additional debug code, binary incompatible with level 1 and 2 (aka DBG_UTL)

Everything beyond that should either be "#if 0"'ed or "#ifdef DEBUG_${MODULE}_${AREA}".

Opinions? If there are no objections, I would file Easy Hacks for that.

Best,

Bjoern