Fix 2 "Condition is always true" compiler warnings.
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index df49d0d..39d4d72 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -471,7 +471,7 @@
                 else {

                     return 0;

                 }

-                TIXMLASSERT( digit >= 0 && digit < 16);

+                TIXMLASSERT( digit < 16 );

                 TIXMLASSERT( digit == 0 || mult <= UINT_MAX / digit );

                 const unsigned int digitScaled = mult * digit;

                 TIXMLASSERT( ucs <= ULONG_MAX - digitScaled );

@@ -501,7 +501,7 @@
             while ( *q != '#' ) {

                 if ( *q >= '0' && *q <= '9' ) {

                     const unsigned int digit = *q - '0';

-                    TIXMLASSERT( digit >= 0 && digit < 10);

+                    TIXMLASSERT( digit < 10 );

                     TIXMLASSERT( digit == 0 || mult <= UINT_MAX / digit );

                     const unsigned int digitScaled = mult * digit;

                     TIXMLASSERT( ucs <= ULONG_MAX - digitScaled );