Begin doxygen-compatible comments

src/uint256.h

@@ -19,8 +19,9 @@ inline int Testuint256AdHoc(std::vector<std::string> vArg);
 
 
 
-// We have to keep a separate base class without constructors
-// so the compiler will let us use it in a union
+/** Base class without constructors for uint256 and uint160.
+ * This makes the compiler let u use it in a union.
+ */
 template<unsigned int BITS>
 class base_uint
 {
@@ -393,6 +394,7 @@ typedef base_uint<256> base_uint256;
 // uint160
 //
 
+/** 160-bit unsigned integer */
 class uint160 : public base_uint160
 {
 public:
@@ -507,6 +509,7 @@ inline const uint160 operator-(const uint160& a, const uint160& b)      { return
 // uint256
 //
 
+/** 256-bit unsigned integer */
 class uint256 : public base_uint256
 {
 public: