Depedit

* 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

Added conditions on sentence annotations, for example:


tok=/!/;S:type=imperative 2>1 1:xpos=IMP_MARKER


i.e. find a sentence with a comment ` type = imperative` and only then apply the rule to the contained token '!'

This adds a bugfix to 2.2.0.

Added conditions on sentence annotations, for example:


tok=/!/;S:type=imperative 2>1 1:xpos=IMP_MARKER


i.e. find a sentence with a comment ` type = imperative` and only then apply the rule to the contained token '!'

* Bugfix head criteria to use in-sentence ID rather than global ID
* Add xpos and upos aliases