update for ConceptNet 5.4; add URIstd for standardization feature

[kengz]

Hi, I notice it's been a while since the last update, and there's considerable changes in ConceptNet 5.4. Can you review the PR and publish it so we can use the latest ConceptNet?

changes:

• Update to be compatible with ConceptNet 5.4
• Add URI standardization
• Search in ConceptNet 5.4 is for finding edges. Update the tests and docs
• update docs and tests

[coveralls]

Coverage remained the same at 100.0% when pulling 8257873 on kengz:master into dfbe1b1 on Planeshifter:master.

[kengz]

Forgot to mention, this resolves #4

[kengz]

@Planeshifter can you pls announce when the new package is published to npm? Would love to use it ASAP thx.

[Planeshifter]

Thanks for your additions and help! I am right now improving my code a bit and will publish a new version tonight (in not more than three hours).

[Planeshifter]

New version 0.3.0 of the package is online. I changed the name of the URIstd method to getURI to make it more descriptive.

[kengz]

Thanks