STY: Change ITK_OVERRIDE for override in whole code (find Modules -type f -exec sed -i 's/ITK_OVERRIDE/override/g' {} +)

Simplify the code and avoid some allocations to improve performance.

I haven't checked the definition of RealType, but merging the output and
value variables might arguably affect precision. The unit tests still
seem to pass, however.

Tested by 2x upsampling a 10-band 5490x5490 float32 image on an Intel
Celeron J1900.

There is further room for improvement by eliding the remaining memory
allocations. A container like the small_vector from Boost might be
useful here, but we can't use that since it's not available in older
Boost versions.

before:
661.44s user 9.31s system 304% cpu 3:40.52 total
594.06s user 9.43s system 303% cpu 3:19.00 total
591.15s user 9.43s system 301% cpu 3:19.28 total

after:
443.42s user 10.48s system 294% cpu 2:34.00 total
443.11s user 9.87s system 309% cpu 2:26.27 total
448.50s user 10.50s system 311% cpu 2:27.52 total

Simplify the code and avoid some allocations to improve performance.

I haven't checked the definition of RealType, but merging the output and
value variables might arguably affect precision. The unit tests still
seem to pass, however.

Tested by 2x upsampling a 10-band 5490x5490 float32 image on an Intel
Celeron J1900.

There is further room for improvement by eliding the remaining memory
allocations. A container like the small_vector from Boost might be
useful here, but we can't use that since it's not available in older
Boost versions.

before:
661.44s user 9.31s system 304% cpu 3:40.52 total
594.06s user 9.43s system 303% cpu 3:19.00 total
591.15s user 9.43s system 301% cpu 3:19.28 total

after:
443.42s user 10.48s system 294% cpu 2:34.00 total
443.11s user 9.87s system 309% cpu 2:26.27 total
448.50s user 10.50s system 311% cpu 2:27.52 total

    Where available, use c++11 features to identify
    potential nullptr usage errors.

    python run-clang-tidy.py -clang-tidy-binary ~/software/clang+llvm-3.8.0-x86_64-linux-gnu-ubuntu-14.04/bin/clang-tidy -checks=-*,modernize-use-nullptr -header-filter=/home/grizonnetm/projets/otb/src/OTB/Modules/.*/.*/include/.* -j8 -fix -p ~/projets/otb/bin/release/OTB-clang3.8/ ~/projets/otb/src/OTB/Modules/*/*/src/*.cxx ~/projets/otb/src/OTB/Modules/*/*/app/*.cxx ~/projets/otb/src/OTB/Examples/*/*.cxx ~/projets/otb/src/OTB/Modules/*/*/test/*.cxx > ~/temporary/run-clang-tidy-nullptr-log.txt

    find . -type f -print -name "*.h" -o -name "*.txx" -o -name "*.cxx" |xargs perl -pi -e 's/nullptr/ITK_NULLPTR/g'

Used the following command:

find . \( -iname *.txx -and ! -path *ThirdParty* \) -exec perl -pi -w -e 's/__otb(.*)_txx/otb$1_txx/g;' {} \;
find . \( -iname *.h -and ! -path *ThirdParty* \) -exec perl -pi -w -e 's/__otb(.*)_h/otb$1_h/g;' {} \;

Fixes many, but not all, clang -Wreserved-id-macro warnings.

    clang-tidy tool can insert missing override keyword as a macro so that missing [optional] virtual identifiers can be easily added.

    build otb with clang 3.8 and use cmake option CMAKE_EXPORT_COMPILE_COMMANDS=ON. Most modules and third parties have been activated.

    #Save override occurences in otb code
    cd src/Modules ; grep -nR "override" * > ~/temporary/override_otb.txt

    #Run clang modernize check using utility script which allow to process the code in parallel
    python run-clang-tidy.py -clang-tidy-binary ~/software/clang+llvm-3.8.0-x86_64-linux-gnu-ubuntu-14.04/bin/clang-tidy -checks=-*,modernize-use-override -header-filter=/home/grizonnetm/projets/otb/src/OTB/Modules/.*/.*/include/.* -j8 -fix -p ~/projets/otb/bin/release/OTB-clang3.8/ ~/projets/otb/src/OTB/Modules/*/*/src/*.cxx ~/projets/otb/src/OTB/Examples/*/*.cxx ~/projets/otb/src/OTB/Modules/*/*/test/*.cxx > ~/temporary/run-clang-tidy-log.txt

    #Replace override by ITK macro (to maintain compat with c++98)
    find . -type f -print -name "*.h" -o -name "*.txx" |xargs perl -pi -e 's/\ override/\ ITK_OVERRIDE/g'

ENH: Removing old method to calculate streaming parameters in StreamingTraits, and removing useless base class