Macrofied higher-order functions for method definition.
Tweaked readme.
Retain vector type when negating

Fixes #13
Merge pull request #15 from jayschwa/negation

Retain vector type when negating
Addresses #14. Generalized the mapMethod function to work with binary operators.
Add some core tests for scalar operations
Merge pull request #17 from dronir/master

Add core tests
Generalized scalar type in scalar binary ops.
Add outer constructors for Vectors

VectorN(a1::T,a2::T,...) will create a typed VectorN{T}.
Add cross() for Vector3
Added barebones matrix types. (No constructors or math yet.)
Merge pull request #19 from jayschwa/cross-product

Cross product
Merge branch 'master' into travis-ci
Fix Travis CI config target "before_script"