Setup Travis CI phpseclib user home directory accordingly.
Use pwd instead of ls. If the directory is empty callback will not be called.
Merge pull request #307 from bantu/travis-home-directory

Setup Travis CI phpseclib user home directory accordingly.

* bantu/travis-home-directory:
  Use pwd instead of ls. If the directory is empty callback will not be called.
  Setup Travis CI phpseclib user home directory accordingly.
A few functional tests for Net_SFTP.