nitdoc: fix assets url in makefile

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
lib: intro String::rmdir

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
android: generate Android project in a subdirectory of .nit_compile

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
android: delete the Android project folder prior to generating code

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
Merge: nitdoc: fix assets url in makefile

Should fix #551

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

Pull-Request: #553
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>
Merge: Clear the Android project folder before generating files

Should solve a problem encountered in #507 where two different Nit projects were compiled into the same Android project.

Pull-Request: #550
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>
Reviewed-by: Jean Privat <jean@pryen.org>