Routine Name:	tweaktau

Description:	Allows one to fill the A table of a tabchannel with the
		activation time constant tau, and the B table with the steady
		state activation m_inf, and then convert the tables to the
		proper values A = alpha and B = alpha + beta.

Usage:		tweaktau channel-element gate
		gate	X, Y, or Z

Example:	tweaktau Na_rat_smsnn X

Notes:

See also:	tabchannel, tweakalpha
