Alphatwirl

Changes from the previous release: ([diff](https://github.com/alphatwirl/alphatwirl/compare/v0.20.2...v0.20.3))
- made the default format for `float` in the output data frame the
same in python 2 and 3.
- updated the test for pytest 4
- updated the tag line, replacing "multi-dimensional" with "multivariate"
- stopped sleeping needlessly in `TaskPackageDropbox` [\54](https://github.com/alphatwirl/alphatwirl/pull/54)

Changes from the previous release: ([diff](https://github.com/alphatwirl/alphatwirl/compare/v0.20.1...v0.20.2))
- stopped letting `receive_one()` in `TaskPackageDropbox` unnecessarily
unpickle all available results, which was needlessly consuming
memory [\51](https://github.com/alphatwirl/alphatwirl/pull/51)
- fixed a bug in `_deprecated(msg)`. didn't work correctly when `msg`
was not given.

Changes from the previous release: ([diff](https://github.com/alphatwirl/alphatwirl/compare/v0.20.0...v0.20.1))
- allowed duplicate dataset names in `EventDatasetReader` [\50](https://github.com/alphatwirl/alphatwirl/issues/50)

Changes from the previous release: ([diff](https://github.com/alphatwirl/alphatwirl/compare/v0.19.0...v0.20.0))
- added `collect()` to `AllwCount`, `AnywCount`, `NotwCount`
[\33](https://github.com/alphatwirl/alphatwirl/issues/33)
- `mkdir_p()` checks if `path` is empty
- added unittest for `mkdir_p()`
- avoided mutable default of `ReaderComposite`, `AllwCount`,
`AnywCount`.
- removed the implementation of
`build_progressMonitor_communicationChannel()`, `atdeprecated()`,
`atdeprecated_func_option()`, `atdeprecated_class_method_option()`,
`atrenamed_func_option()`, `atrenamed_class_method_option()`
- were deprecated
- now, raise `RuntimeError` if called
- added a decorator `_removed()`
- reimplemented `TableFileNameComposer`
- fixed `ProgressPrint`, avoiding changing dict during iteration

Changes from the previous release: ([diff](https://github.com/alphatwirl/alphatwirl/compare/v0.18.8...v0.19.0))
- removed deprecated sub-packages: `cmsedm`, `delphes`, `heppyresult`.
- the contents of these packages can be found, respectively, in
the following repositories:
- https://github.com/alphatwirl/atcmsedm
- https://github.com/alphatwirl/atdelphes
- https://github.com/alphatwirl/atheppy

Changes from the previous release: ([diff](https://github.com/alphatwirl/alphatwirl/compare/v0.18.7...v0.18.8))
- fixed an import error at rtd