Objective-C FFI: intro the FFI with Objective-C

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
tests: add a general test for Objective-C without a framework

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
misc: vim syntax recognize the Objective-C syntax

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
misc: trigger for extern code blocks of Java, C++ and C are more tolerant

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib/cocoa: intro the cocoa library to wrap cocoa, foundation and app_kit

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib/cocoa: intro the Hello World example in Cocoa

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib/cocoa: intro message box example in cocoa

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
lib/cocoa: intro an example with extern Objective-C classes

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
tests: add option to skip tests per OS

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
tests: add OS skip list for Linux and cocoa

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
nitni: add indirection to use `MModule::c_name` without all the compilers

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>