Update Rust micro benchmark

- use ndarray crate for randmatstat and randmatmul by default
- enable direct BLAS use with a cargo feature
- provide rust-toolchain override file
- fix trace calculation in randmatstat
- other code refactors

Author: Enet4

test/perf/micro/rust/Cargo.lock

@@ -1,11 +1,27 @@
 [package]
 name = "julia-bench"
 publish = false
-description = "Rust implementation of the micro benchmark"
 version = "0.1.0"
 
 [dependencies]
-blas = { version = "0.15.4", features = ["openblas"] }
+itertools = "0.7.1"
 mersenne_twister = "1.1.0"
-num = "0.1.39"
+num = "0.1.37"
 rand = "0.3.15"
+
+[dependencies.blas]
+features = ["openblas"]
+version = "0.18.1"
+optional = true
+
+[dependencies.blas-sys]
+version = "0.6.9"
+features = ["openblas"]
+
+[dependencies.ndarray]
+features = ["blas"]
+version = "0.10.12"
+
+[features]
+default = []
+direct_blas = ["blas"]

test/perf/micro/rust/Cargo.toml

@@ -0,0 +1 @@
+nightly-2017-10-28