Update to cgmath 0.18

Author: nstoddard

Cargo.toml

@@ -33,16 +33,15 @@ name = "collision"
 
 [dependencies]
 rand = "0.6"
-approx = "0.3" # Only for the macros; for all other instances use the re-exported cgmath ones.
-cgmath = "0.17"
+approx = "0.4" # Only for the macros; for all other instances use the re-exported cgmath ones.
+cgmath = "0.18"
 serde = { version = "1.0", optional = true, features = ["derive"] }
 bit-set = "0.5"
 smallvec = "0.6.1"
 
 [target.'cfg(feature="serde")'.dependencies]
-cgmath = { version = "0.17", features = ["serde"] }
+cgmath = { version = "0.18", features = ["serde"] }
 num = { version = "0.2", features = ["serde"] }
 
 [dev-dependencies]
 genmesh = "0.5"
-