Folia-tools

Minor bugfix release:

* alpino2folia: sanitize FoLiA ID from filename

[Maarten van Gompel]
* folia2stam: do not include leading whitespace in token/structure offsets

[Ko van der Sloot]
* foliaspec: added 1 line to the C++ code generation, enabling a light for of type introspection
* foliaspec: "feat" should NOT be in the list of features that can be attributes

* folia2stam: added debug mode + fixed text untangling to properly regard text delimiters
* tei2folia: implemented --docid parameter to set document id 56

[Maarten van Gompel]
* folia2stam: added initial version of folia2stam conversion, using stam-python 0.4.0, might still be subject to change
* transcribedspeech2folia: added conversion script for transcribed speech with speaker diarisation output (plain text) to FoLiA
* foliaspec: upgraded yaml loading
* foliaspec2rdf: updated RDF conversion for FoLiA v2.5.3
* removed support for Python 3.6

[Ko van der Sloot]
* foliaspec: added XML processing instruction support for C++ only (Python parser doesn't support it)

* [tei2folia] Fixed regression bug 46
* [tei2folia] Implemented support for c and rs elements.

* foliatextcontent: Implemented the ability to add offsets to existing elements 43
* foliatextcontent: fix for processor in linkstrings (LanguageMachines/PICCL63)