KBucket.getContact expects guid, not contact object.
Searches for contact among existing contacts always failed in KBucket.getContact when called from OptimizedTreeRoutingTable.addContact.
[WIP] removing pysqlcipher sources from the repo.

Travis builds are taking too long due to double installations of pysqlcipher,
the second installation which runs from pip seems to be doing fine now, if there
are any issues left in pysqlcipher we'll fix them upstream as suggested by @dionyziz
Merge pull request #755 from gubatron/bye-bye-pysqlcipher-sources

removing pysqlcipher sources from the repo.
Merge pull request #745 from freamon/bugfixes

Fix for DB writes
Abstract the Elliptic Curve used; setup initial testsuite.

* Introduce crypto_util.BTC_CURVE as the curve's name. Replace any
  magic strings in the codebase with crypto_util.BTC_CURVE.
* Invoke pyelliptic.OpenSSL to get curve ID
* Abstract the key length.
Abstract and test public and private key processing.

* pubkey_to_pyelliptic now returns key in bin format.
* Replace hexToPubkey with pubkey_to_pyelliptic.
Create and test a Cryptor class to abstract pyelliptic.

* Replace makePubCryptor, makePrivCryptor and ec.ECC with Cryptor.
* Provide the ECC key getters; do not keep the keys in Cryptor class.
* Purge pyelliptic imports outside crypto_util.
* Purge most references to _myself; let's not be self-centered.