Law

Core:
- Exclude Python < 3.3
- Refactor file system configuration and permissions (local and remote)
- Accelerate get_param_values when values are not modified
- Refactor sandboxing mechanism
- Fix target stage-in/-out for sandboxes
- Argument-safe sourcing in shell scripts
- Accelerate deep status text queries for target collections
- Refactor handling of missing job ids in remote workflow
- Add localize_{input|output} convenience methods
- Add `localize` decorator
- Add interactive `--print-output` parameter
- Interpret integer types as plain ranges for creating branch map
- Make decorators aware of generator functions
- Minor updates

`docker` / `singularity`:
- Move docker/singularity sandbox implementations to contrib packages

`git`:
- Refactor git repository bundling

- Refactor htcondor job status queries.
- Autocompletion support for zsh.
- Improve JobFileFactory configuration.
- Fix home dir for remote jobs.

- Updated docker images, added latest CERN CA certs
- Refactored configuration of remote targets and file systems
- Fixed bug regarding cache size allocation for remote files
- Made remote job wrappers configurable in workflows
- Renamed `law db` to `law index`
- Added zsh autocompletion
- Updated license to BSD-3-clause

- Add telegram notifications
- Add hooks for remote workflows to quickly configure their `JobFileFactory` and `JobManager` instances
- Fix GFAL installation in Docker images
- Fix `chmod()` bug for local targets
- Fix `isdir()` for remote targets, esp. for SRM with custom file type bits in stat
- Refactor submission and job status polling in remote workflow

Features:

* Added notification module and decorator
* Mail notifications
* Slack notifications
* Refactored remote workflow polling

Fixes and internals:

* Fixed bug in log decorators
* Fixed TeeStream
* Minor fixes in local and remote targets regarding file copying
* New mechanism to add run decorators on workflow proxies
* Minor fix in CascadeMerge contrib task

- Fixed bug in `util.iter_chunks` which affected `contrib.task.CascadeMerge`
- Added mechanism to send notifications after tasks run
- Added `slack` contrib package for slack chat notifications