Memory limit raised from 70MB to 1GB

Liberty BASIC has supported a 70MB working space for the development environment and also for the runtime engine.  This limitation was imposed for garbage collection performance reasons, but with the size of computer RAM today being in the gigabyte range it made sense for us to upgrade this.  Now with Liberty BASIC v4.5.0 the limit has been raised to 1GB.  This is 14x more memory for your program code and data to run in.