smalltalk: Make sure that TCL/TK is disabled when building it
smalltalk: Make it work with the latest Poky version

* disable dev-so for the plugin libraries
* split into more packages
misc: Use RDEPENDS_${PN} to avoid warnings on new poky
iliad: Add grease and add more dependencies to it
smalltalk: Enable the readline support on the cli

The detection code appears to distinguish between libedit (BSD
re-implementation of readline) and GNU readline and it does that
by executing the code.