eliminate static arrays and MAXSIDES limit (#1081)

* test side index, enemies, and relations

# Conflicts:
#	src/battle.test.c

* eliminate the enemies array

* replace the static per-side relations array with a hashmap

* unused variable & code in test

* stdint and stdbool require C99

* eliminate MAXSIDES from get_row

* simple test for get_unitorw (deserves more testing)

* use dynamic strings in lieu of yet another big fixed buffer.

* MAXSIDES is gone