build - Add flextls to setup.py
src - Use flextls to scan for server ciphers

* Don't do a full handshake (refs #1)
* Limit number of ClientHello packages (refs #2)

This is a proof of concept.
src - Use data from flextls as cipher info
src/scan - Use cipher suites form flextls
build - Update install requirements
src/report - Use new data structure
src/rating - Rename protocol version rating
src/scan - Move SSLv3/TLS scan into function
src/scan - Use new lib to scan for SSLv2 ciphers
src - Remove openssl from core
src/scan - Use functions provided by core
src/scan - Add base function to scan TLS ciphers

* Add function to BaseScan() class to scan for TLS ciphers
src/scan - Improve detection of preferred ciphers

* This fixes #3
src/report - Improve preferred cipher results
src/scan - Use core function to detect TLS ciphers
src/scan - Use named curve info from registry
src/scan - Use hash + signature info from registry
src - New Timeout exception
src/scan - Handle exceptions
src/scan - Handle exceptions