Merge pull request #14 from jastix/num

docs&specs, _n.nonzero, _n.floor, _n.zero
Exposed RubyJS in the main package.json's export

Made the following possible:
```
{ R } = require('rubyjs')
```
Typo
Merge pull request #16 from TobiaszCudnik/master

Exposed RubyJS in the main package.json's export
Merge pull request #15 from jastix/num

docs&specs. _n.upto, _n.even, _n.gcd
add _s.size and _a.size
specs for _a.size and _s.size
rename RWrapper to Chain
fix Cakefile
ruby bump
docs&specs. _n.next, _n.pred, _n.round