Allow 'update' and 'buildjni' to accept list of subdir paths to run tools within.

Allow 'update' and 'buildjni' to accept list of subdir paths to run tools within.

This is useful for multi-component projects (main app + libraries in separate
dirs). Older adhoc values (update=no, buildjni=yes) for both options are
retained, except that to ignore jni/ directory, buildjni=no instead of
buildjni=manual should be used now.

Also, if --verbose is given, print message about runnibg ndk-build - native
libraries can be quite big and process long, so this is useful to keep user
in loop. To achieve this, had to global'ize options.