LablGtk 3.1.2

Bug fixes and a few new bindings

Changes:

2021.12.24[Jacques]

• Remove naked pointers and Obj.truncate for compatibility with 5.00 (#144)

2021.12.18 [Jacques]

• Add WRAP_WIDTH, WRAP_MODE tags to cell_properties_text (#146)
  [Nathan Guermond]
• Add bindings for applying CSS from a string (#134) [Bart Jacobs]

2021.12.03 [Jacques]

• Cherry-pick #142 [Bart Jacobs]
  (Fix #141: lablgtk2 runs OCaml code inside blocking section)

2021.07.05 [Jacques]

• Update scrollbar handling in GText.view for gtk3 (#124) [Vasile Rotaru]
• Add partial support for OCaml 5.00 (#129) [Kate Deplaix]
• Fix warnings on Bytes_val

2021.03.15 [Jacques]

• Add bindings fro GtkStack and GtkStackSwitcher (#122) [Hugo @swarmpan]

2020.08.31 [Jacques]

• Fix #116 : problem with GPack.layout adjustments (reported by Vasile Rotaru)