Transformation up to v0.8.7

When either you (as a transformed monster) or your captured monster defeats an enemy, experience in the form of green balls drops. This experience can be collected by your captured monster but gives you no benefit. When picked up by you (as a transformed monster), this experience is collected and can be used to unlock further transformations at the Transformation table.

Transformations available include:
 * Wisp
 * Slime
 * Snow Slime
 * Sand Slime
 * Cavern Slime
 * Night Crawler
 * Scorpion
 * Repty
 * Snow Repty
 * Sand Repty
 * Sand worm