#324 Add basic explanations of a project's build configuration files.
#324 Improve description of Package/Components.cmake files.
#324 Further documentation improvements of typical configuration files.
#324 Modify Settings.cmake example to use CMAKE_COMPILER_IS_GNUCXX.
#324 Detail sections regarding header files, installation prefix, testing, and custom project layout.
Merge remote-tracking branch 'github/feature/#324configHowTo' into develop

Conflicts:
	doc/howto/configure-project.rst