Dvc

1) Introduced `--dot` option for `dvc pipeline show` that will output the pipeline in a dot format, that can be then rendered with graphviz. Kudos pared .
2) Fix bug in ssh remote driver where it would as several times for password when performing `dvd pull`;
3) Add a note about default behavior to `dvc remove` help message;
4) Removed unused code;

1) Updater README links;
2) Updated requirements for pip;
3) Replaced cffi with ctypes;

1) Stopped using pyreflink module due to maintainer's unresponsiveness;
2) Now building osx packages on OS X 10.11 in order to provide forward compatibility;

1) State file now uses sqlite database instead of json file;
2) Introduced configurable limits for state file size;
3) Introduced configurable cleanup quotas for state file;
4) Fixed bug in `dvc repro --dry` where it was checking for missing dependencies;
5) Fixed bug in `dvc run` where it was producing empty dvc files when ran without arguments;
6) State and link state files are now combined into single `.dvc/state`;
7) Fixed bug in dvc where it was scanning unnecessary directories looking for dvc files;
8) Fixed bug in `dvc run` where it was allowing to specify `-f` with subdirectories, causing following `dvc repro` to fail;
9) DVC now lists files that it has changed and tells that they could be added with git;
10) Added ability to configure password for SSH remote;
11) Introduced `-p|--pipeline` option for `dvc repro` to reproduce the whole pipeline that the specified dvc file belongs to;
12) Fixed bug in ssh remote driver where it was hanging if there were too much files on the remote;
13) Support git submodules; Kudos jeepkd;
14) Introduce `-d|--with-deps` option for `dvc pull/push/fetch/status`;
15) Fixed bug in `pull/push` progress bar where it was showing improperly joined paths on windows;

1) Fix recv() bug in ssh remote;
2) Fix bug with deps that don't exist;

1) Add ability to configure timeout for ssh remote;
2) Properly handle io when executing commands on the remote host through ssh;