add_dependencies: Disallow use with INTERFACE_LIBRARY.
add_library: Error on source listing for INTERFACE_LIBRARY.
Style: Use this-> when invoking member function.
install: Rename variable referencing cmake version.

The next version is 3.0.0, not 2.8.13.

The version generated in the export file should be updated in
the release branch in both cmExportInstallFileGenerator and
cmExportBuildFileGenerator.
cmTarget: Rename container holding link implementation objects.

Don't erroneously name it for the link implementation. That's
something different.
Help: Remove workaround for pre-CMake 2.8.4 code.

The requirement was updated in commit 920ffbf5 (Require CMake 2.8.4
or greater to build CMake, 2013-10-11) and similar snippets were
removed.
Help: Workaround pygments reporting an error for genexes.

Without the workaround, CMake code snippets are not highlighted
at all because pygments can not lex the generator expressions.
export: Only generate and install configuration files if needed.

The modern way to create configuration dependent content is using
generator expressions in the main export file.  The only non-deprecated
property still generated in the configuration-specific files are
IMPORTED_LOCATION_<CONFIG>

INTERFACE_LIBRARY targets have no location, and no need for those
files.
install: Ensure that install(TARGETS) works with no DESTINATION

INTERFACE_LIBRARY targets have no corresponding files, and so
require no DESTINATION to install anything to.
Merge topic 'minor-cleanups' into next

942a521 install: Ensure that install(TARGETS) works with no DESTINATION
369320c export: Only generate and install configuration files if needed.
d5bda1b Help: Workaround pygments reporting an error for genexes.
7b0c8ec Help: Remove workaround for pre-CMake 2.8.4 code.
58b58a9 cmTarget: Rename container holding link implementation objects.
82c4455 install: Rename variable referencing cmake version.
5206774 Style: Use this-> when invoking member function.
590aa9d add_library: Error on source listing for INTERFACE_LIBRARY.
13ab715 add_dependencies: Disallow use with INTERFACE_LIBRARY.