change logging module

[mxriverlynn]

the logging module currently provide an @logger to any class that includes it. this should be changes to use a module level variable, such as Albacore.logger so that the logger is always available, everywhere, not just in modules / classes that include the logging module

[mxriverlynn]

this introduces issues with the current logging levels that are settable in each specific task instance, though. example:

msbuild do |msb|
  msb.log_level = :verbose
end

this wouldn't work if every access to the logger was from a class level attribute. will have to re-think this and/or decide if i just want to delete the ticket.