add documentation to import public key from modulus and exponent

Travis checks for Node v6

Sometimes we find the need to daisy chain or nest functions, and I felt that returning "`this`" would allow that to happen. This would let people do stuff like
`new NodeRSA().importKey(...)`, although `new NodeRSA(...)` would technically be advantageous

NodeRSA.importKey() now returns this

bump version & update readme

We should be able to deal with any random cruft outside of the BEGIN and
END boundaries.

Make the pkcs1 format more accepting of surounding content

…s for pkcs1 & pkcs8.

Allow keys without BEGIN/END boundaries to be loaded

Validate correct objects in tests

version bump

fix: Change let - var for  es5 compatible

 fix: Change let - var for es5 compatible

version bump