readme: 64-bits
64-bit check during import
brian interop (work in progress)
readme: MAP link
readme: run_zilany2014.py direct link
todo: neuron interop
improve holmberg2007 vesicles example
small stats/examples changes
fix bug in holmberg2007 channel iterator

improvements in quantal mode
stats rate_level: tone_duration as an argument
readme cleanup: installation moved to docs