correct response for PWD
remove binary mode checks
remove unneeded check for CTRULIB
Merge pull request #6 from WinterMute/fix-env-variable

remove unneeded check for CTRULIB
Merge pull request #5 from WinterMute/remove_binary_mode

Remove binary mode
print command when it was invalid
no-op USER and PASS
implement MKD
implement DELE
implement RMD
implement RNFR and RNTO
remove TODO note from MODE
Merge pull request #1 from mtheall/master

sync upstream