changed to Unlicense, added license file

v0.1.2

changed to Unlicense, added license file

bugfixes; added RvalDerefAlloc, RvalFieldByPathAlloc

• Bugfix: TraverseStruct and TraverseStructRval no longer attempt to
  traverse nil embedded struct pointers.

• TraverseStruct and TraverseStructRval now allow a nil struct
  pointer as input, without traversing its fields. This behavior is
  consistent with nil embedded struct pointers.

• Added RvalDerefAlloc.

• Added RvalFieldByPathAlloc.

v0.1.0

init