Update to ngspice-23 from ngspice-20.  From the NEWS file:

Ngspice-23, June 5th, 2011
============

- New features:
    + Reduction of trtol to 1 only if 'A' devices in the circuit and xspice is enabled
    + command wrs2p to write a s-parameter file using Touchstone vers. 1 format
	+ d_source d_state d_ram, test cases for those xspice codemodels
	+ transient noise simulation added to independent voltage and current sources
	+ Random telegraph noise added to independent voltage and current sources
	+ 'time = nnn' in stop command added
	+ random voltage generator option trrandom to independent voltage and current sources
	+ ngspice build possible in a separate directory (e.g. in ng-spice-rework/release)
	+ update FIND .. WHEN measurements
	+ diode & bjt temperature model update with tlev and tlevc
	+ merge bsim3v1a code with bsim3v0 and bsim3v1s code with bsim3v1
	+ bjt2: removed - all GP extensions of this model are now in the bjt model
	+ HiSIM_HV model vers. 1.2.1 added
	+ bsim3v32: delvto and mulu0 as instance parameters
	+ Replace HiSIM1 by HiSIM_2.5.1_Release_20110407

- Bug fixes:
    + More on prototypes, type casts, reordering of functions, compiler warnings
	+ allow models like 2N2904 or 2SK136 also in subcircuits
	+ fix sensitvity calculation (for the dc-2+.cir testcase)
	+ allow multiple call to setup w/ correct node collapsing
	+ Many small bugs

Ngspice-22, Sept 26th, 2010
============

- New features:
    + OpenMP multicore support for BSIM3, BSIM4, and BSIMSOI4
    + reinstate {$var} expansion in interactive interpreter
    + .TITLE line added
    + update to 'spectrum' script
    + par('expression') in .four, .plot, .print, .meas, .save commands
    + command 'option' for use in spinit, .spiceinit, and in scripts
    + adms procedure updated
    + new random number generator, random functions sunif() and sgauss()
    + ngspice manual updated

- Bug fixes:
    + Major code cleanup to reduce compiler/linker warnings: ansi function prototypes,
      void/char pointers to named pointers, explicit type casts and many more
    + Many small bugs

Ng-spice-rework-21, Jun3, 13th 2010
============

- Updated Devices: BSIMSOI 4.3.1

- New features:
    + Compatibility: C, L, R, devices and E, G sources with expressions
	  Variables HERTZ, TIME, TEMPER added
    + E, G sources with pwl function
    + New manual
	+ Plotting with Gnuplot,
	+ Writing wrdata for simple text table to file
	+ .measure improved
	+ transmission line models improved

- Bug fixes:
    + Many small bugs, memory leaks, memory overflows


(dmcmahill)