* FullPivLU: replace "remaining==0" termination condition (from Golub) by a fuzzy compare

(fixes lu test failures when testing solve())
* LU test: set appropriate threshold and limit the number of times that a specially tricky test
  is run. (fixes lu test failures when testing rank()).
* Tests: rename createRandomMatrixOfRank to createRandomProjectionOfRank

test/inverse.cpp

@@ -42,7 +42,7 @@ template<typename MatrixType> void inverse(const MatrixType& m)
              m2(rows, cols),
              mzero = MatrixType::Zero(rows, cols),
              identity = MatrixType::Identity(rows, rows);
-  createRandomMatrixOfRank(rows,rows,rows,m1);
+  createRandomProjectionOfRank(rows,rows,rows,m1);
   m2 = m1.inverse();
   VERIFY_IS_APPROX(m1, m2.inverse() );