Remove the fixed image used for reference

The displacement field can be used as a reference image to resample
the transform onto. An additional function was added which takes two
transform and a reference image.

Change-Id: I3195844f1b6080b613ced5c378822434f6a7491e
Adding TRANSFORM_COMPARE option to sitk_add_test

Adding arguments to sitk_add_test to compare the results of test
program. This is useful to check the output of examples and other test
processes which don't perform the comparison internally to the test.

Change-Id: I1f21772d9f91d87b60983f9b7697af0edd176a03
rename cmake support file with sitk prefix

Change-Id: I2b31b098b40f755757069bf7247558b6df26ded4
Moving sitk custom add test function to separate cmake file

Change-Id: Ib2e0425e3133ac67377f97e16b10773fb058bbcf
rename variable SITK_DATA_ROOT to SimpleITK_DATA_ROOT

SimpleITK is used in more project name type variable as opposed to a
scoping prefix where SITK is used.
Move python add_test wrapper to separate cmake file

Change-Id: Iccbeb4ef606ff6e4aa55a72f9adf569e9abc2b81
Moving CXX Example testing to examples directory

Change-Id: I55a235dbd23f83ab44cb8c59701a074068fd21c2
Moving python example tests to example directory

Change-Id: I85615e047d46cf1ad6c66a86bc2ea526924b8bf1
Moving Ruby Lua and TCL example tests to example directory

Refactored the language specific add_test wrapper to the common cmake
file. Added ExternalData references to tests.

Change-Id: I9c3cc282f513893aa4d40207d8afcc00977f06e0
remove check for build examples from add tests

Since the example tests are not in the examples directory this
conditional is implicit with the directory structure.

Change-Id: I5d26fc6b47f090b12237b22ab845b55538e03faa
Merge topic 'SIMPLEITK-536_CreateTransformTestingInfrastructure' into next

41157a2a remove check for build examples from add tests
1c62b2d7 Moving Ruby Lua and TCL example tests to example directory
76d64645 Moving python example tests to example directory
bd25df83 Moving CXX Example testing to examples directory
e94feff6 Move python add_test wrapper to separate cmake file
4c2c4d2c rename variable SITK_DATA_ROOT to SimpleITK_DATA_ROOT
585390b1 Moving sitk custom add test function to separate cmake file
03c387f0 rename cmake support file with sitk prefix
b1ee2782 Adding TRANSFORM_COMPARE option to sitk_add_test
3068c220 Remove the fixed image used for reference