Add function to myantcompile.el to add import at the beginning of a Java source
file, using a class name given interactively (C-b a i) or using the name
at point (C-b i).
For the moment, only standard JRE class are supported, unless a FQN is provided.
It a later commit I will add a function to scan current project classes and find
automatically a suited import, as for standard library classes.