BUG: post_build on windows appends all commands

See merge request orfeotoolbox/otb!91

BUG: change ParameterFile ext to None

See merge request orfeotoolbox/otb!94

Fix itk packaging

See merge request orfeotoolbox/otb!83

Solve empty default value doc

See merge request orfeotoolbox/otb!88

BUG: error generating qgis descriptors

See merge request orfeotoolbox/otb!87

below commit uses POST_BUILD and PRE_BUILD to generate a fresh copy of
descriptor files for all OTB applications.
orfeotoolbox/otb@b963a177

This has broken dashboard due to a dependency issue.
https://dash.orfeo-toolbox.org/buildSummary.php?buildid=318175

otbQgisDescriptor is not dependent on any otb applications and it is
TRUE. But it has a run-time dependency to all otb applications when we
auto-generating all depscriptors. This situation forces us to add a
dependency so that POST, PRE building targets works. These are only
executed if otbQgisDescriptor target is rebuilt hence, it is not run
everytime with make.

Revert of the initial commit[2] is to get source tree in to a stage which
was reviewed. The first version of post,pre build was pushed directly to
release rather than via MR. Current state in release-6.6 will result in
broken dashboard.

[2] orfeotoolbox/otb@3f7b6d40

PKG: disable dl test for python wrappings (GDAL)

See merge request orfeotoolbox/otb!85

PKG: small exception for check on /usr path with libdrm

See merge request orfeotoolbox/otb!84

Resolve "Error during OTB SuperBuild compilation on Ubuntu 16.04"

See merge request orfeotoolbox/otb!82

This reverts commit b963a177.

BUG: #1567: fix compilation with GDAL 2.3.0

See merge request orfeotoolbox/otb!79

Fix installation of GDAL bindings in standalone packages

See merge request orfeotoolbox/otb!78

Resolve "wrong default RGB composition for Pleiades image"

See merge request orfeotoolbox/otb!73

Use OGRSpatialReference class to compare projref

See merge request orfeotoolbox/otb!65

Add new contributors and refer to CONTRBUTING.md in the SG

See merge request orfeotoolbox/otb!60

Resolve : Application can't be launch through monteverdi

See merge request orfeotoolbox/otb!70

DOC: allow the configure step to print detected Qt5 version

See merge request orfeotoolbox/otb!76

Review: "add Wrapper/QGIS to generate qgis descriptors for processing plugin"

See merge request !74

descriptors are generated with a custom target called
'generate_descriptors'. It depends on all OTBAPP.txt
So a missing .txt during installation will try to generate txt file.
This make sure all available applications have a valid descriptor.
There is a internal custom target called clean_descr which depends on
otbQgisDescriptor executable. This target re-create an empty directory
set in OTB_INSTALL_DESCR_DIR under OTB_BINARY_DIR. This make sure every
execution of generate_descriptor target is a clean one.

Finally, custom target is executed by make install using cmake's
install(CODE. Users can either can "make generate_descriptors" manually
or is automatically called during install.