Removed a C-style cast.
Magic number reduction
Silence some expected formula warnings
Fix some error messages
Add WML unit tests to travis
Fix [store_unit]kill=yes (bug #22007)
next_hop(): bug fix for ignoring units when ignore_units=true is set

A bug in the previous version let to them not being ignored when  the
were on the last hex of the next hop.
Tutorial: add Delfador animation to summon extra quintains
Fix bug #21448: make premoved units selection like in Wesnoth 1.10
Add missing newlines at EOF
Fix Doxygen comment.
Avoid a useless cast.
Remove an unneeded semicolon.