Added new options for sftp: chiphers,  macs, compressions.

A good settings for high performance:

    [swftp]
    ...
    chiphers = blowfish-cbc
    macs = hmac-md5
    compressions = none
Makes Chipher/Mac/Compression Config List Parsing Reuse Code
Merge pull request #1 from softlayer/sirkonst-chiphers

Makes Chipher/Mac/Compression Config List Parsing Reuse Code
Merge pull request #30 from sirkonst/chiphers

Added new options for sftp: chiphers,  macs, compressions.