Fix: WYSIWYG now returns valid HTML in tables

The WYSIWYG by default creates invalid HTML5. Creating a table and running it through W3C validator returns the following error: The border attribute on the table element is obsolete. Use CSS instead.
Update i18n.md

Fix a link being inside backticks, which broke the formatting.
Merge pull request #3171 from ss23/patch-4

Update i18n.md
Update datamodel.md

Fix broken link to SS_List->column
Merge pull request #3172 from stevie-mayhew/patch-1

Update datamodel.md
Update i18n.php

Norwegian should use 'nb' and not 'no' in common languages array
Merge pull request #3231 from tscole/patch-2

Update i18n.php
FEATURE allow force resampling on images
Better encoding of javascript
Fixes #2988
Merge pull request #3269 from tractorcow/pulls/3.1/convert-js-enhancements

Better encoding of javascript
Merge pull request #3265 from stevie-mayhew/images-force-resample

FEATURE allow force resampling on images
BUG Config::merge_array_low_into_high() ignores falsey values

Specific case: LeftAndMain::$session_keepalive_ping = true cannot be
set to false in config.yml for some cases because the value is ignored
when merge_array_low_into_high() is processing the config arrays.
Merge pull request #3272 from halkyon/config_fix

BUG Config::merge_array_low_into_high() ignores falsey values
Merge pull request #2998 from torleif/patch-4

Fix: WYSIWYG now returns valid HTML in tables
Revert "BUG Config::merge_array_low_into_high() ignores falsey values"
Merge pull request #3275 from silverstripe/revert-3272-config_fix

Revert "BUG Config::merge_array_low_into_high() ignores falsey values"
Fatal errors should always return false

This allows PHP to set the exit code on fatals.
Merge remote-tracking branch 'origin/3.0' into 3.1

Conflicts:
	i18n/i18n.php
Updating the WAMP docs to include composer installation and apache 2.4 fix - delete index.php

Now uses GFM for code blocks.
Merge pull request #3268 from camfindlay/wamp-docs

Updating the WAMP docs to latest version and include composer installation notes