Making more of the stuff optional

Improving adjustability of the footprint. New configs seem to allow
binary size between 60kB to 120kB depending on configuration.

Signed-off-by: Olli Vanhoja <olli.vanhoja@gmail.com>
Use linker set to declare pre- and post-scheduling tasks

Signed-off-by: Olli Vanhoja <olli.vanhoja@cs.helsinki.fi>
Cleaning-up BCM UART code a bit
Fixed code formatting and added configurability to some error messages

Signed-off-by: Olli Vanhoja <olli.vanhoja@cs.helsinki.fi>
Use linker sets to define kloggers

- Refactored kerror to use linker sets
- Renamed lastlog logger to kerror_buf
- Added fb logger
Merge branch 'rt' of github.com:OlliV/zeke into rt
Fixed merge conflict and added some comments

Fixed some compilation errors and warnings that came after the merge
from untested code.
Fixed FB logger

There is a bit critical issue if FB logger is set as a default klogger
because kerror can't have a dependency to actual fb drivers and fb
abstraction doesn't know if there will be any FBs registered ever. So
essentially this causes kerror to write to FB too early before
initialization is ready.

Possible solution for this kind of problems might be to add a "querying"
interface to harware abstraction subsystems that would try to init all
drivers in a known linker set. Then other modules could have true
dependecy to the abstraction level. This of course doesn't remove the
problem with issues if still no devices have been actually registered.
Removed unnecessary make config files for this branch
Cleaning up code base
Centralized init for framebuffer for nicer dependency handling.

Signed-off-by: Olli Vanhoja <olli.vanhoja@cs.helsinki.fi>