Conservative elimination of !null checks before 'delete'

C++ guarantees that delete 0 and delete [] 0 do nothing.
Older buggy compilers that didn't honour this are no longer
supported by VTK.  Conservatively removed many "if (!ptr)"
checks before using delete in /Common.

Change-Id: Idf185d675e516e7fb5a8a745fd3dbf9720035325
ProjectVector method was modifying plane normal.

Thanks to David Jarvis for pointing out this bug.  Projecting a vector
would cause the plane's normal to be multiplied by the dotprod of the
plane and the vector (in some cases, causing the normal to become zero).
Obviously the ProjectVector() function should not modify the normal.

Change-Id: Idaa86fdad897777a65fba6f8ac5309a3582175e6
MetaIO: Removed the deprecated _CM24 CMake variables

These were introduced for CMake 2.4 installation paths, and were
deprecated in favor of VTK_INSTALL_*_DIR variables.

Author: Marcus D. Hanwell <marcus.hanwell@kitware.com>
Removed the deprecated _CM24 CMake variables

These were introduced for CMake 2.4 installation paths, and were
deprecated in favor of VTK_INSTALL_*_DIR variables. Ported existing code
to use these variables, removed the old declarations and removed some
unused CMake code in Utilities/Release instead of porting it forward.

Change-Id: I67ba95016eeb8536ebda8b8e44b30c9f2177744e
Merge topic 'plane-project-vector' into master

ba3c24c3 ProjectVector method was modifying plane normal.
Fix set-but-not-used warnings in Domains/Chemistry tests.

Change-Id: I54643fdc5079de1f2f52b51a94af5bfe9301f6ab
Merge topic 'remove-CM24-vars' into master

2f5fdb13 Removed the deprecated _CM24 CMake variables
Merge topic 'chemistry-warnings' into master

41ddc334 Fix set-but-not-used warnings in Domains/Chemistry tests.
Merge topic 'if-before-delete' into master

890a9760 Conservative elimination of !null checks before 'delete'