#1687 fix for calendar feed when date format is different from YYYY-MM-DD

This fixes tasks and other modules dates not appearing in calendar feed because of the user date format different than 'YYYY-MM-DD'.

See merge request !856

Fixes #1597 and #1604 - Avoid lineitems deletion when using vtws_revise

See merge request !858

Fixing Documents not being sent as Email Attachments #1506

When sending Email and adding a CRM Document as an attachment, the Document was not sending due to missing filepath value
Fixes #1506

See merge request !847

removing CKEditor spell check which is broken

#1685 removing broken spell check in CKEditor

See merge request !852

align account register address with sign-in page

The account register mail address shown in the `README.md` is not identical to the address in the [sign-in page](https://code.vtiger.com/users/sign_in).

I believe the `community @ vtiger.com` is the correct address since the mail sent to `info @ vtiger.com` was never replied.

See merge request !853

Fixes #1688 in order to improve global search efficiency

See merge request !855

Fixes #1689 which prevented saving multipicklist fields in quick create

See merge request !857

getSelectedDefaultTaxMode #1561

Finally the obnoxious error that denied vtws_create, vtws_revise and more operations, since 4 years ago, is solved.
Now you don't have to patch it manually at every release anymore.

See merge request !848

popuptranslated #1684

this fixes a long lasting problem for popup calendars not picking translated strings for user set language

See merge request !850

minilist with 4 columns  #1589

Strangely it was already fixed by me but it wasn't in master so I changed the code in a tidier way that hopefully will be merged!

See merge request !851

fix for #1677

This merge requests fixes a problem preventing google events to sync in vtiger.

See merge request !846

Fix for UI10 type fields for issue #1657

Css fix for displaying correctly uitype 10 fields in detail view, when opened for editing value.

See merge request !845

fix dates filter issues on #1666 and #1638

fix dates filter for every module, even reports.

See merge request !844

allow unlinking related items if you can edit the parent item fix #210

deleting a relationship should require edit access to the parent object (the one they are related to) not delete access to the target object. (because you are not deleting it, just disassociating it which is an edit to the parent object)

See merge request !70

Issue #1002 MainManager exception while fetching related items

Also, detecting sent emails to compare with current user email

See merge request !321

standalone #1639 mailconverter custom actions

With this modification it's possible to add custom actions to mail converter just like custom workflow function! New action would be displayed along with default actions.

Follow this example:
```
require_once('modules/Settings/MailConverter/handlers/MailScannerEntityMethodManager.inc');
$emm = new MailScannerEntityMethodManager($adb);
$moduleName='HelpDesk';
$methodName='createticketcustom';
$functionName='createticketcustom_helpdesk';
$functionPath='modules/yourmodule/yourmoduleHandler.php';
$emm->removeEntityMethod($moduleName, $methodName);
$emm->addEntityMethod($moduleName, $methodName, $functionPath, $functionName);

See merge request !838