start new features documentation for 3.5

Documentation/Books/Manual/Installation/Compiling.md

@@ -6,7 +6,7 @@ Mac OS X systems, as well as on Windows.
 
 We assume that you use the GNU C/C++ compiler or clang/clang++ to compile the
 source. ArangoDB has been tested with these compilers, but should be able to
-compile with any Posix-compliant, C++11-enabled compiler. 
+compile with any Posix-compliant, C++14-enabled compiler. 
 
 By default, cloning the GitHub repository will checkout the _devel_ branch.
 This branch contains the development version of the ArangoDB. Use this branch if

Documentation/Books/Manual/ReleaseNotes/NewFeatures35.md

@@ -0,0 +1,16 @@
+Features and Improvements
+=========================
+
+The following list shows in detail which features have been added or improved in
+ArangoDB 3.5. ArangoDB 3.5 also contains several bug fixes that are not listed
+here.
+
+Internal
+--------
+
+We have moved from C++11 to C++14, which allows us to use some of the simplifications,
+features and guarantees that this standard has in stock.
+To compile ArangoDB from source, a compiler that supports C++14 is now required.
+
+The bundled JEMalloc memory allocator used in ArangoDB release packages has been
+upgraded from version 5.0.1 to version 5.1.0.

Documentation/Books/Manual/ReleaseNotes/README.md

@@ -7,6 +7,7 @@ What's New
 For a high level list of changes, please refer to one of the following sections:
 
 - What's New in 3.x:
+  [3.5](NewFeatures35.md),
   [3.4](NewFeatures34.md),
   [3.3](NewFeatures33.md),
   [3.2](NewFeatures32.md),