Refs #0001   Adding python script that "DNSifies" NDN names

Script takes an input a URI formatted NDN name and output (if possible)
a converted DNS name:

  - order of name components gets reversed: /x/y/z.n/m -> m/z.n/y/x
  - all "/" replaced with ".": m/z.n/y/x -> m.z.n.y.x
  - the resulting name is checked for validity, and if necessary (and
    possible), converted to international domain name

Change-Id: I745be9ca89bd86f773a56c2da147364d67fda6ac
Refs #0001    Implementing load of public key certification, meta, and public key name from .pubcert file, which has fixed name "<keystore_file>.pubcert"

Change-Id: Ia641355199018960dcec05aa453a531c20c32c98
Refs #0001   Implementing request for public key name

Also in this commit:
- command line tool (ndn-pubkey-name) to retrieve stored public key name

Change-Id: I28b903f41d6174dfc07edbeb23dadac8e02b1375
Refs #0001    New helper script ndn-install-pubcert to check and install .pubcert file into the right location

Change-Id: Idcf066f292ebf898d59fb70d178bf60aa142c014
Refs #0001   Two more helper scripts: to extract public key and to automate application key signing

ndn-sign-key is a simplified version of the original script from
http://github.com/named-data/ndn-testbed-key-suite repository, which
combines usage of .pubcert and published keys to infer most of the
signing parameters.

Change-Id: I86607f1d581d61eaf773296af46ed8243f84d7bb