Changes from 0.1-1 to 0.1-2
	* donlp2.control(): add fnscale tag to execute maximization easily.
	* following tags returned from donlp2() changed:
	  - $hessian: hessian matrix
	  - $nr.update: upper triangular cholesky factor
	* donlp2.c - tagnames for the list(return value) are specified in C.
	* Document fixes.
Changes from 0.1-2 to 0.2-1
	* Rdonlp2.c - use ef(), efgrad(), econ(), econgrad() instead of eval_extern to run the optimization more efficiently.
	* Rdonlp2.c - many of bugs that cause 'memory not mapped' error might be fixed.
Changes from 0.2-1 to 0.2-3
	* donlp2.c - fixed the bug that output of gresn[] on console were wrong values.
	* Rdonlp2.c - no more include donlp2's header files.
	* donlp2.c - changed definitions of user_init_size(), user_init(), setup(), solchk so that auguments are passed by address.
	* *.h - all the variables are declared static.
	* donlp2.c - commented out unused variables. Now compiler should issues no warnings with -Wall option.
	* donlp2.c(o8st) - tolmac = DOUBLE_XMIN, epsmac = DOUBLE_EPS.
Changes from 0.2-3 to 0.2-4
	* Rdonlp2.c: ef(), econ() now accepts the second value from eval() to make use of ffuerr and confuerr[].
	* donlp2.c: change definitions of ef(), econ() to accept arguments ffuerr and confuerr[] respectively.
	* Rdonlp2.c: the list returned now includes w[](penalty term for constraints).
	* donlp2.c: change definitions of solchk() and newx() to pass w[]
Changes from 0.2-4 to 0.3-1
	* changes for ef(), econ(), solchk(), newx() made in 0.2-4 are discarded(revert to original intefaces).
	* Rdonlp2.h, o8xxxx.h: all global variables but need to use in Rdonlp2.c are declared static. 
	* donlp2.c: init_global_vars(): new function. all global and static variables used in donlp2.c are *explicitly* initialized at the head of donlp2().
	* donlp2.c, Rdonlp2.c: added hessian and calc_hessian variables for hessian caliculation
	* donlp2.c: eshessf(): new function. caliculate numeric hessian at the optimum by numerical differention with specified value in difftype.
	* Rdonlp2.c: teardown(): new function. various finalizer(free memory allocated in donlp2.c and close file handles for .mes/.pro files)are collected in this function.
	* donlp2.R: donlp2() now call "call_donlp2" within try-catch-finally framework.
	* donlp2.c: .pro and .mes files are no longer created unless 'name' argument in donlp2() is explicitly specified.