msg bufferisation

Hi,

I added an option to msg() to bufferize output. I made context() use it, this makes it print everything at the same time and reduces the visual disturbance while repeatedly doing 'next instruction' in gdb. (At least in my opinion.)

I don't really care if you merge this into master or not, but if your are interested and you have any questions or remarks on the code I'll be glad to help!

Regards,
wapiflapi