Depedit

Bug fix capturing groups

* Experimental support for splitting tokens (adding a token) using split= action
* Added storage3 field for additional hidden storage
* Faster execution by earlier abandonment of non-matching rules and definition priority sorting
* Bugfixes

This is a bug fix release addressing cases in which existing enhanced dependencies could not be overwritten by additional enhanced dependencies between the same pair of tokens.

* multiple edits to the same token pair are now possible in sequence
* only the latest write operation is retained in the rule output

* Added `-=` subtraction operator for removing features from FEATS and MISC
* Better ordering for comment lines
* Performance improvements and bug fixes

* Add support for making supertokens (MWTs) with `><` operator
* Add option `-t, --text` to generate sentence ` text =` comment
* Add storage and storage2 convenience fields (can be used to save intermediate manipulations, do not get serialized)
* Add operators for querying and adding multiple concurrent enhanced dependencies (`1~2`, fields `edep` and `edom`, see [documentation](https://github.com/amir-zeldes/DepEdit/blob/master/docs/DepEdit_user_guide.pdf))
* Make invokable as a module (`python -m depedit`) when installed

* better enhanced edge manipulation with `edep`, `edom` and `~` operator
* support pipe-separated features using `+=` action
* implement UD validator-conforming feature and edep sorting
* use `once` directive to apply rules only once per sentence
* added `storage` pseudo field for temporary value storage
* added examples for English morphology and enhanced dependency enrichment
* minor bugfixes and updated documentation