Bug 479451 - Warning for projects without explicit encoding

Add a warning marker to projects without explicit encoding. The warning
is meant to encourage setting an explicit encoding to all projects, so
that the workspace default encoding can change without breaking
projects.

Change-Id: Id112603856a334447d5d504adc874f769a1daa80
Signed-off-by: Simeon Andreev <simeon.danailov.andreev@gmail.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.resources/+/192052
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Andrey Loskutov <loskutov@gmx.de>
15 files changed