* Convert `ec` to the rzshell
* Port the `echo` command
* Make the `color` argument optional for `ecHw`
* Remove `rz_core_echo`
* Make `echo` a part of `e` commands
* Add tests for `eco` and `ecHw`
* Move the definition of `bool2status` to `cmd_eval.c`
* Fix `ecHj` and add a test for it