RustDCT

RustDCT is a pure-Rust signal processing library that computes the most common Discrete Cosine Transforms:
- DCT Type 1
- DCT Type 2 (Often called "the" DCT - by far the most common algorithm, used by JPEG image compression and others)
- DCT Type 3 (the inverse of the DCT type 2, also used in JPEG)
- DCT Type 4
- MDCT (Used in audio and video compression such as Ogg and MP3)
Example
```rust
// Compute a DCT Type 2 of size 1234
use rustdct::DCTplanner;
let mut input: Vec = vec![0f32; 1234];
let mut output: Vec = vec![0f32; 1234];
let mut planner = DCTplanner::new();
let mut dct = planner.plan_dct2(1234);
dct.process(&mut input, &mut output);
```