add the renamed spec

renamed spec for credential class
forgot to add it
more cleanup work

some code and documentation DRY work
more documentation work

added some more YARD docs
cash host resolution

if we successfuly resolve the host during
the validation, then alter host to the resolved
address to avoid the overhead of subsequent
DNS requests.
Merge remote-tracking branch 'upstream/master'
allow scan! to take a blcok

by allowing scan! to take block
and yield the result of each attempt
we can do things like have a module print out
status messages
Merge pull request #1 from rapid7/feature/ssh_login_scanner

SSH LoginScanner class
nake scan! more generic

scan! can now be reused for each scanner and
only attempt_login is specific for each thing.
Merge branch 'feature/ssh_login_scanner' into staging/electro_release
Merge branch 'master' into staging/electro_release
add the mixins for tcp and ftp

skimmed down, non-module dependent mixins
for TCP client and Ftp client. neccesary for
loginscanner work
first pass of FTP LoginScanner

made the first pass at the ftp
LoginScanner, with base specs.
Need to still tierate, add more new
specs and clean it up
touchups and specsfor FTP Scanner

add some final touchups and specs to the FTP
Loginscanner object. now fully working.
Merge branch 'master' into staging/electro_release
add sshkey loginscanner

added the loginscanner class for SSHKey and
the base specs
add proxies to ssh scanner

allow the SSH LoginScanner
to accept a proxy directive
Add metasploit-credential to gemfile

add a temp reference to the metasploit-credential
gem to the gemfile. Need this for access to ssh key
factories for tests
fix spec filename

had an extra underscore
Finalized specs for sshkey

shkey loginscanner now compelte along
with specs
Merge branch 'bug/9582-metasploit-imports-and-tasks'

Land #3299