Better support for CoNLLU format and some new features
* New ".*" operator shorthand for unlimited adjacency (e.g. `1.*2` instead of `1.1,10002`)
* New value identity operator, e.g. `1:text==2` means that `1` and `2` must have the same text
* Better control of batch file mode output file names (see --help)
* Automatic insertion of new document and incremental sentence ID tokens
* Support for ellipsis tokens with decimal point IDs (e.g. ID=5.1)
* Bug fixes for better Python 3 compatibility