Minor bug fixes and enhancements

Fixes: #1505, #1484, #1479, #1474.

Changes:

• Full support of PDF page rectangles like /ArtBox etc.
• New global variable TESSDATA_PREFIX for comfortably checking presence of OCR support
• Changed Document.xref_set_key() such that dictionary keys will physically be removed if set to value "null".
• Changed Document.extract_font() to optionally return a dictionary (instead of a tuple).

New features for class Pixmap and several fixes

Fixes:
#1351, #1417, #1418, #1430, #1433

• New or changed Pixmap methods color_topusage(), color_count(), warp(). Some of them solve #1397.
• New Annot method and property irt_xref, set_irt_xref(). Implements #1450.
• New Rect / IRect method torect() which creates a matrix to transform between given rectangles.
• Page.get_texttrace() now also supports non-horizontal text.

Improvements for drawings extraction and bug fixes

Improvements:

• Page.get_drawings() now includes area orientation for rectangles
• Page pixmap creation has a new parameter "dpi"
• New check for monochrome / unicolor pixmaps and number of colors

Fixes:
#1388, #1375, #1364, #1342, #1355, #1397, #1408.

Important improvements for OCR support

OCR of a document page has been improved a lot compared to v1.19.0.
Text extractions now also come with an integrated sort.
Fixes: #1328

First version to support MuPDF v1.19.*

Introduces major new features like PDF journalling and OCR support by directly invoking Tesseract-OCR.
In addition, it is possible to detect whether object are covered (hidden) by other objects.

As part of the new version, the following issues have resolved:
#1313, #1311, #1290, #1286, #1287, #1284.

Hotfix

Fixes #1266

Implement various fixes

This version fixes #1257, #1252, #1244, #1241, #1234, #1236, #1227.

Performance improvement for drawings extraction

improve test scripts

`show_pdf_page` and `insert_image` are now tested with rotated insertions.

Layout Preserving Text Extraction

The fitz module now supports text extraction via a new subcommand "gettext". Among a couple of modes, preserving the original layout can be chosen.

Also fixed #1187, #1184, #1154, #1152 and #1146.

Support of Small Capitals, assigning subset font name tags

Apart from some minor fixes, this release introduces support for small caps in TextWriter based text output.

In addition, method Document.subset_fonts() now prefixes subsetted font names with the 6 upper case letter prefix as prescribed by the PDF standard.

List of fixed issues:
#1088, #1081, #1078, #1085.