'make.names.jm' makes syntactically valid R names out of a 
character vector (as does the make.names function).  It differs from 
make.names insofar as terminal periods (.) are deleted if possible, 
'and successive periods, e.g., "..", are optionally reduced to ".".

ARGUMENTS:

'names.jm' is a character vector to be turned into valid R object names.

'unique.jm = TRUE' (default) guarantees that the names are unique.

'rm.double = TRUE' (default) reduces repetitions of periods to single periods, e.g., 'x..y' is converted to 'x.y'.  

'allow_.jm = TRUE' (default) allows underscores in the names.

The na.to.F function has been deprecated in favor of the NA.to.F function.  Please replace "na.to.F" with "NA.to.F" in all JM function code.  The na.to.F function will be retained for awhile but it will eventually be deleted.  Current date = 12/30/2013.

'na.to.F' converts a logical vector that may contain some NA's to a logical vector of the same length in which every NA is replaced with FALSE while leaving all existing TRUE's and FALSE's as they are.

'NA.to.F' converts a logical vector that may contain some NA's to a logical vector of the same length in which every NA is replaced with FALSE while leaving all existing TRUE's and FALSE's as they are.

Function 'nxt' resets the current graphics device.  

If 'w = NA' (default), then 'nxt()' resets the current graphics device to the next graphics device on the device list.  If no graphics devices are currently open, then 'nxt()' opens a graphics window using the default values in the 'windows.jm' function.  

If 'w = <N>' where N is an integer, then 'nxt(N)' resets the current graphics device to N-th device on the device list.  If N exceeds the number of currently open devices, then nxt opens additional graphics windows until there are N of them.  

NOTE:  R enumerates the open graphics windows starting at 2, so the first graphics window is window 2, the second graphics window is window 3, etc.  The nxt(1) makes window 2 the active window; nxt(2) makes window 3 the active window; etc.