Folia-tools

* 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)

* [foliavalidator] added a --fixinvalidreferences parameter to fix (=delete) invalid wref references (proycon/flat174)
* [folia2txt] implemented support for retrieving the original text of a document prior to any corrections 40

* folia2columns: added option to extract sentences and paragraphs and support for extracting sequences of lemmas, pos, poshead, sense or phon when extracting paragraphs or sentences (thanks to Jelke Bloem) 36 37
* folia2columns: if outputting to a single file, no longer print header multiple times when processing multiple files (thanks to Jelke Bloem)
* tei2folia: implemented an --intermediate option to dump intermediate output
* tei2folia: can handle certain pseudo-TEI now 35
* fix for table in pseudo-TEI paragraph
* Accept teiTrim as a valid root element, despite this NOT being an actual valid TEI element!
* foliaspec: added a mapping to the C++ properties (Ko van der Sloot)
* foliahtml: updated folia2html test output
* python 3.5 is deprecated now, use 3.6 or higher