#248 Add TEMPLATE_DIR CMake variable for custom project template configuration.
Modify basis_use_package to do nothing if module dependency is BASIS.

Clearly when the basis_use_package(BASIS) command is called in basis_project_impl of a module, the BASIS package must be available already. Otherwise, these commands would not exist. Further, the top-level project already included the BASISUse.cmake file through basis_use_package called by basis_project_impl within the root CMakeLists.txt of the top-level project.
Exclude mercurial repository files as well.
Merge branch 'develop' into feature/add-template-dir-cmake-variable

Conflicts:
	data/CMakeLists.txt
Fix installation of custom project template files. (incl. CMakeLists.txt).
Change project template directory structure and default template options.
Fix configuration of sbia/1.8 project template.
Move PROJECT_TEMPLATE from root CMakeLists.txt to TEMPLATE argument of basis_project in BasisProject.cmake.

Do not use full path for TEMPLATE argument if template is part of the BASIS installation.
Merge branch 'feature/add-template-dir-cmake-variable' into develop
Merge commit '0666c27359625d7266b034f4f23303301c9d84d0' for allowing basis as a module of a basis project into develop from issue #256 https://github.com/schuhschuh/cmake-basis/issues/246
Issue #237 Correct dead links in Basis Introduction. Also improved clarity and updated outdated parts of the presentation to match the 3.0 release.
Merge tutorial improvements and origin branch into basislogo branch.