Re-do pull request #451 export CMake targets with PROJ4:: namespace

This version takes to add the include path to the target definition for
cmake 2.8.11 and later.  Also the documentation sticks to the existing
convention of using cmake variables ${PROJ4_LIBRARIES} and
${PROJ4_INCLUDE_DIRS}.  However, the namespace variables are still being
included.

Here's the roll-out plan

(0) Version 4.9.x: The target is proj and PROJ4_LIBRARIES is set to
this.

(1) Version 5.0.x: Two targets, proj and PROJ4::proj, are defined;
PROJ4_LIBRARIES = proj.

(2) In a year or two: Two targets, proj and PROJ4::proj, are defined;
PROJ4_LIBRARIES = PROJ4::proj.

(3) With a change in the library which breaks backwards compatibility:
The target is PROJ4::proj and PROJ4_LIBRARIES = PROJ4::proj.

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/source/development/index.rst b/docs/source/development/index.rst
index 2e6e5622..712bbdfe 100644
--- a/docs/source/development/index.rst
+++ b/docs/source/development/index.rst
@@ -14,4 +14,4 @@ proj.4 project or using the library in their own software.
    api
    threads
    bindings
-
+   cmake