Merge pull request #1280 from DiamonDinoia/readme-remove-cxx14-note

Update README after C++14 requirement

Author: JohanMabille

README.md

@@ -104,7 +104,7 @@ http://xsimd.readthedocs.io/
 |   9.x   |     ^0.7.0       |
 |   8.x   |     ^0.7.0       |
 
-The dependency on `xtl` is required if you want to support vectorization for `xtl::xcomplex`. In this case, you must build your project with C++14 support enabled.
+The dependency on `xtl` is required if you want to support vectorization for `xtl::xcomplex`.
 
 ## Usage