Computes the brat2-th power of brat1.

Prototype
   brat BigRat.pow( brat1 , brat2 )

Parameters
   brat1 and brat2
      Positive big rational.

Return Value
   This function returns a big rational which represents the brat2-th power of brat1

Remarks
   brat1 and brat2 must be created before function call.

Example
    
require( "BigRat.lua" )

a = BigRat.new( "25" )
b = BigRat.new( "2" )
c = BigRat.pow( a , b )
print( "POW = " .. c )
   
Output
    
POW = 625