Add required dependencies, formatting

Cargo.toml

@@ -7,15 +7,15 @@ homepage = "https://github.com/rust-bitcoin/rust-bip39/"
 repository = "https://github.com/rust-bitcoin/rust-bip39/"
 documentation = "https://docs.rs/bip39/"
 description = "Library for BIP-39 Bitcoin mnemonic codes"
-keywords = [ "crypto", "bitcoin", "bip39", "mnemonic" ]
+keywords = ["crypto", "bitcoin", "bip39", "mnemonic"]
 readme = "README.md"
 edition = "2018"
 
 [features]
-default = [ "std" ]
-std = [ "alloc", "serde/std", "unicode-normalization/std" ]
-rand = [ "crate_rand", "rand_core" ]
-alloc = [ "unicode-normalization" ]
+default = ["std"]
+std = ["alloc", "serde/std", "unicode-normalization/std"]
+rand = ["crate_rand", "rand_core"]
+alloc = ["unicode-normalization"]
 
 # Note: English is the standard for bip39 so always included
 chinese-simplified = []
@@ -37,21 +37,27 @@ all-languages = [
     "japanese",
     "korean",
     "portuguese",
-    "spanish"
+    "spanish",
 ]
 
 [dependencies]
 rand_core = { version = ">=0.4.0, <0.7.0", optional = true }
 crate_rand = { package = "rand", version = ">=0.6.0, <0.9.0", optional = true }
-serde = { version = "1.0", default-features = false, features = [ "alloc" ], optional = true }
+serde = { version = "1.0", default-features = false, features = [
+    "alloc",
+], optional = true }
 
 # Enabling this feature raises the MSRV to 1.51
 zeroize = { version = "1.5", features = ["zeroize_derive"], optional = true }
 
-# Unexported dependnecies
+# Unexported dependencies
 bitcoin_hashes = { version = ">=0.12, <=0.13", default-features = false }
 unicode-normalization = { version = "0.1.22", default-features = false, optional = true }
 
+# faster PBKDF2 implementation
+fastpbkdf2 = { git = "https://github.com/invd/rust-fastpbkdf2.git", branch = "master" }
+itertools = { version = "0.8" }
+
 [dev-dependencies]
 # Enabling the "rand" feature by default to run the benches
 bip39 = { path = ".", features = ["rand"] }