Support for Slot Swapping

My changes are in comments, so no actual code change. Uncomment to
enable them. I'm sure you know that.

Skills that move attacker end combat
(future note: but will resume abilities and combat if another card is
swapped into its place.)
Skills that move defender will end combat or target new card if target
slot is empty or filled with a follower, respectively.
Added Spells

200228 - Everyday Life
200229 - Meeting
200230 - Summer Day Memory

200237 - True Vampire God

200301 - Cobalt Book
200302 - Hiking Lesson
200304 - Protection
200308 - Quick as the Wind
Lots of Spells and Engine support for them
Spells and some engine edits to ease them
Bugfixes
Bugfixes and rewrites
Bugfixes
Engine combat rollback
Bugfix
Merge pull request #16 from lightalkmst/master

Spellz