Release v0.0.5_1

This is mainly a bugfix release with some updates of C interface for relkinema v0.5.5.

• FIX: "deint" recognized as a parameter when dummy argument
  specification was omitted.
• FIX: 2++! causes error.
• FIX: mod(1,0) cause FIGFPE to abort.
• FIX: 0! returns 0.
• FIX: exp(huge returns I.finity + I.finity i
• FIX: .delete does not work.
• FIX: .exp does not work after .eng
• FIX: a=0;a+=i results in 0.
• FIX: a=1;a++ does not set a=2.
• FIX: 1 ++2=(1++)2=22=4
• FIX: 4/-2=-2 but 4/ -2 = error.
• FIX: f(x)=2x;f(1);f(2)/ans returns wrong result. rpnc%answer is modified during
  function/macro/integrand evaluation.
• FIX: 2e3**2=2e9
• FIX:
  f(y)=deint_x(x+y,0,y
  deint_y(f(y),0,1
  *** deSdx: BUFFER OVERFLOW
• FIX: plus/minus after logical operators turns to binary.
• FIX:
  *** Syntax Error at:
  f(a=1,b=2,c=3
  ^
• FIX: semi-colon not processed correctly at eval.
• FIX: plus/minus after blank turns to unary.
• FIX: .byte mode is broken.
• FIX: .eng mode is broken.
• FIX: 1;2; prints 2
• FIX:
  * Syntax Error at:
  mysin(x)=(exp(ix)-exp(-ix))/2i;
  ^
• FIX: function and macro assignment exits main loop of interactive mode.
• FIX:
  *** Syntax Error at:
  m="pi;"
  ^
• FIX: sin(pi) prints 1.22464679914735
• FIX: f(x)="x=2;sin(x)"
  ** Warning: Unused parameter: x
• FIX:
  f(x)="pi;c;x"
  Warning: Unused/useless variable: x
  No such parameter: x
  *** Syntax Error at:
  f(x)="pi;c;x"
  ^
• New operator !_ to calculate multi-factorial for positive integers;
  n!_1=n!, n!_2=n!!.
• New stat flag RCS_SRC_SET is cleared/set by set_formula.
• rpnc%sd now local for macro.
• Binary filename changed to fzcalc.bin which is executed via bash script fzcalc.
• c is now writable.
• integer values are now stored in 8-byte format by default.
• BUG: factorials ! and !! incomplete for real arguments.
• BUG: 3.5!! returns wrong result.
• BUG?: "deSdx" too slow for functions with edge singularity.
• BUG: f(x)="1x,2x,3x" returns no error.