ENH: Begin ITK 4.14 development cycle

Bump 'ITK_VERSION_MINOR' from 13 to 14 and reset 'ITK_VERSION_PATCH' to
0.  This commit opens a new 4.14 maintenance branch derived from
'v4.13.3' and carrying the CMake 3.5 / C++11 / GCC 4-20 build-support
work in the preceding commits of this PR.

Scope of the 4.14 branch

  4.14 is a build-infrastructure-only line.  No new ITK algorithms,
  classes, IO formats, or APIs are added; users targeting 4.14 see the
  same library surface as 4.13.3 with a refreshed set of compiler and
  CMake version constraints:

    * CMake 3.5 - 4.x (range form '3.5...3.30')
    * C++11 (CMAKE_CXX_STANDARD 11 REQUIRED)
    * GCC 4.8 - 20+, Clang 3.3+, MSVC 2017+ (existing detection plus
      this PR's gcc-cascade extension)

User-facing recommendation

  Users on era-original toolchains predating CMake 3.5 / C++11 (e.g.
  CentOS 7 with system-default cmake 2.8 and no EPEL cmake3) should
  continue using ITK 4.13.3.  4.14 offers no algorithmic benefit over
  4.13.3; only the compiler/CMake version envelope is widened.

  Users blocked from building 4.13.3 because their toolchain is too
  *new* (CMake 4.x dropping pre-3.5 policy support, GCC 11+ refusing
  to compile dynamic-exception-specifications under default C++17,
  CMake's removal of the 'Documentation.cmake' module, etc.) should
  use 4.14.

Author: hjmjohnson

CMakeLists.txt

@@ -41,8 +41,8 @@ set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/CMake ${CMAKE_MODULE_PATH})
 
 # ITK version number components.
 set(ITK_VERSION_MAJOR "4")
-set(ITK_VERSION_MINOR "13")
-set(ITK_VERSION_PATCH "3")
+set(ITK_VERSION_MINOR "14")
+set(ITK_VERSION_PATCH "0")
 set(ITK_VERSION
     "${ITK_VERSION_MAJOR}.${ITK_VERSION_MINOR}.${ITK_VERSION_PATCH}")
 project(ITK