This commit stops considering Langkit_Support as a generated project:
* move the "langkit/support" directory to "support" (not
"langkit_support" for convenience with tab-completion);
* move the meat of the "langkit_support_gpr.mako" template to the static
"langkit_support.gpr" file, and remove the template;
* remove the "build-langkit_support.py" script and all the corresponding
libmanage.py/langkit_support.py code;
* enhance the top-level "manage.py" script to build/setenv
Langkit_Support and import the packaging tools from
"build-langkit_support.py".
From now on, Langkit_Support is a really a standalone library project,
and thus a "real" dependency for Langkit-generated libraries.
TN: T914-012
So far, this testcase assumed that the "langkit" package was in a source
tree, whereas in the Travis CI setup, it comes from the setup.py
installation. Register the build-langkit_support.py script and introduce
PATH lookup in the misc/link_two_libs testcase to make it work on
Travis CI.
TN: T511-017
* Make the setup.py script executable for convenience.
* Enhance langkit_support sources installation procedures in order to
avoid temporary files such as the "obj" directory.
* Update data files list to include Mako templates.
Change-Id: If16aa0b12b274eb1fabd5e24791f5f751874e23b
TN: P210-005
