fixed: removed 'const' from some methods (operators: += -= *= /=) in the Big class

fixed: bad sizes in tables in some 'Set...' methods in the Big class
fixed: Big::FromInt(Int<int_size> value) - the sign must be set at the end because SetSign
       checks whether there is zero and depends on it sets the sign or not
       (this was the stupid error which causes sometimes the errors 'overflow during printing')
fixed: Big::SetMin - the sign must be set at the and
changed: Big::Pow can use the reference now (the problem was actually with the Big::FromInt)
added: a namespace 'auxiliaryfunctions' (in ttmath.h)
added: ATan - arc tan, ACTan - arc ctan


git-svn-id: svn://ttmath.org/publicrep/ttmath/trunk@17 e52654a7-88a9-db11-a3e9-0013d4bc506e

TODO

@@ -4,3 +4,4 @@ TODO TTMath Library
 * to add the method Mod (a remainder from a division) for the Big type
 * to add operators (or functions) and, or, xor
 * to add functions for generating random values
+* to add constructors (UInt, Int) for 64bit platforms (constractors which take int and unsigned)