STYLE: Do not check for version of CMake before including "BundleUtilities"

Since minimum required CMake version for Slicer is 2.8.9, this message
is not needed anymore.
COMP: Ensure Python library directory is considered when fixing up package

When the expression "@SLICER_PYTHON_LIB_DIR@" has been introduced
in commit r21252 [1], it was already resolving to an empty
string because since r15463 [2] the file SlicerBlockCTKAppLauncherSettings is
included in the Applications/SlicerApp/CMakeLists.txt.

Both the fixup script and the launcher settings have been updated to
use the variable "PYTHON_LIBRARY_PATH" introduced in the top-level
CMakeLists.txt by commit r16822 [3]

To prevent such error from happening again, a convenient macro named
"_fixup_paths_append" has been introduced. It basically check if the path
passed as parameter exists and append it to the list of paths. If not,
it throw an error.

[1] http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=21252
[2] http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=15463
[3] http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=16822
COMP: Ensure library paths used for BundleFixup are valid

The helper macro "_fixup_paths_append" is now used consistently to append
path to the "libs_path" variable.

Let's also note the following updates:

 - CMAKE_RUNTIME_OUTPUT_DIRECTORY is not used anymore, instead
${Slicer_BUILD_DIR}/@Slicer_BIN_DIR@ is used.

 - Path "@Slicer_BINARY_DIR@/@Slicer_QtPlugins_DIR@" is not considered
anymore since it didn't exist in the build tree. Instead, the plugin path
are composed using "${Slicer_BUILD_DIR}/@Slicer_BIN_DIR@"
COMP: Do now explicitly fixup CLI shared library

Considering that (1) CLI shared lirbary are dependency
of CLI executable and (2) CLI executable are already discovered by the
fixup mechanism. There are no need to use canidate pattern for CLI
shared library.
COMP: Simplify expression used in gp_item_default_embedded_path_override.
COMP: Remove hack forcing CMAKE_INSTALL_NAME_TOOL to be empty

In commit r21242 [1], CMAKE_INSTALL_NAME_TOOL has been disabled to ensure
the "gp_item_default_embedded_path_override" function could match
library that are expected to go in specific folders like "cli-modules",
"qt-loadable-modules", [...]. By disabling CMAKE_INSTALL_NAME_TOOL,
the match was possible using full path to each one of the
direct dependencies of a given library.

This approach saw its limitation when trying to have CLI executable
installed in "path/to/Contents/cli-modules" and the shared library copied
into "path/to/Contents/lib/Slicer-4.2/cli-modules". Indeed, the shared
library were systematically copied along side the executable in addition
to the the one existing in the "path/to/Contents/lib/Slicer-4.2/cli-modules"
directory.

This commit doesn't do the match based on the full path embedded in the
library, instead it globs for the expected library in the build tree and
then check if a given item name match the list of library "globed" in the
associated directory.

[1] http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&revision=21242