Replaces Array.prototype.reduce with a for loop.

As this is possibly the hottest code path, this speeds up average total
execution time with about 25%, benchmarking shows.
Merge pull request #28 from jbnicolai/fast-js

Replaces Array.prototype.reduce with an explicit loop for performance.
use String constructor rather than + for coercion
Adds benchmarking using matcha.

Run through:
```shell
./node_modules/matcha/bin/matcha benchmark.js
```

Results against current HEAD:
```shell
1,863,195 op/s » add colour
2,215,812 op/s » add several styles
  323,213 op/s » add nested styles
```

Results against the latest revision before optiziations, e122899
```shell
  26,714 op/s » add colour
  26,752 op/s » add several styles
  13,414 op/s » add nested styles
```

Closes #21
Adds performance to readme.
add benchmark to package.json

run with `npm run bench`
bench - minor code style tweaks
bench - increase iterations for more reliable results
use rawgithub to workaround npm website bug with relative image paths
0.5.0
return a new function for each getter

- defines the getters onto a proto
- the function returned has its __proto__ set to our proto

fixes #32
dont use slice on arguments

~21% increase with multiple arguments
Merge pull request #33 from seanmonstar/_styles

fix caching of styles, fixes #32
0.5.1
Bumps escape-string-regexp to 1.0.1, slight speed improvement.
bump deps
Reverses application of styles, now left-to-right

The styles' application order used to to be right-to-left e.g.:
```javascript
console.log(chalk.red.reset.blue('something'))
// red
```

Where now it has been reversed. E.g.:
```javascript
console.log(chalk.red.reset.blue('something'))
// blue
```

It seems to me that this is the more intuitive application order.

Closes #41
Merge pull request #43 from jbnicolai/fix/issue-41

Reverses application of styles, now left-to-right
Updates documentation regarding style application order.
Linewraps at 80 where markdown syntax allows.