This helps systools detect registered name clashes

Also, adapt the rest of lager to use this bitmask as well.

This also removes the dependency on the syntax_tools and compiler
applications, which interfered with lager's startup/shutdown order.

As the include file is located in the same application, using
-include instead of -include_lib removes the need for the
code directory to be called "lager" or "lager-VSN".

The micro-benchmarks show up to 20x improvement, which further
reduces logging overhead.

Helps with pattern matching.

I didn't want the lager_log_message record being used across application
boundaries, this will insulate other applications from any changes to
the message type's internal structure.

Various bugs uncovered during this testing were fixed and added to the
test suite.

Had to add a pseudo-ternary operator to the formatter to support this.
Also allowed lager:log to log metadata.

Also removed commented out code.

There are still differences between the erlang io_lib and the trunc_io in
how ~p/~P are handled, but a first step is useful here.