current behavior
If the option of setToolbarCancelDrawable doesn't set or set with a vector drawable
It will crash on the API 16 or lower

Evidence
com.yalantis.ucrop.UCropActivity}: android.content.res.Resources$NotFoundException: File res/drawable/ucrop_ic_cross.xml from drawable resource ID #0x7f08022d

Version: 2.2.4

Device Info
Name: GT-I8200
Android version: 4.2.2