missing shebang and chmod+x
lot of mods when testing on a bigger project:

- CAKE_BINARY_DIR setting removed
- modules and cfgs set a different set of options
- no system config
- add parents-of-source-dir configs
- simpler combining CAKE_BINARY_DIR_PREFIX/GENERATE_ALWAYS options (always replace)
- fix: options specified on command line were not separated
- some other bugs
- CAKE_LINK_BINARY_DIR option added
trying to make it work with args containing semicolons