initial commit
first unit test
implemented add_elevator and number_of_elevators
implemented number_of_floors in building (w/ tc)
better require
enabled for rake w/ 'test' and 'simulate'
added *.log files to gitignore
logging
configuration is now the optional second parameter of Elevator's initializer
added logging to tc_building
unit test file for elevator
rake :test now executes the elevator tests as well
removed debug code
new attribute 'speed' w/ a default value of 1
new sub module "Core" to provide all methods needed for the simulation