Factorise some code too

Add ability to handle the "caption" property from the dataprovider() to display a title on hover of each option label

Update doc

Just set the 'selected' property to true on the data item
Works also for optgroup's options.

Also use jQuery tag constructor and attribute setter to avoid HTML filtering issues

When updating the button text/title, target only the main button. This allows for additional buttons in templates to remain unaffected. For example, extra buttons in the filter template.

Fixing the initialization of the selected items in the multi-select for Knockout.js binding integration.  Currently a persisted binding value isn't being initialized correctly when using KO.  Instead the selectedOptions are only being set on during the update binding function or when the observableArray is changed.  With this fix, if the observableArray has initial values, they are selected as necessary.s

There is a little correction to the method dataprovider, the parameters for the callback function are index, value.  Probably the problem is that in the forEach method of an array this two parameters are inverted.

Signed-off-by: Tyf0x <Tyf0x@users.noreply.github.com>

Signed-off-by: Tyf0x <Tyf0x@users.noreply.github.com>

Signed-off-by: Tyf0x <Tyf0x@users.noreply.github.com>

Added Array forEach function for browsers that don't support EcmaScript5 (IE 8/9)

-> The deselectall function was deselecting all options regardless of their visibility. It now takes it into account.

-> Fixed a bug where disabled options where incorrectly selected using the 'select-all'
-> Changed the jQuery .not() selector in favor of the css native :not() to slightly improve performance

Divider was not removed on rebuild so each rebuild would add a new divider.

Moving down the onChange callback after this.updateSelectAll() allows to access the correct selected values during the callback.

Use the same format as Select2 : [{children: array (of options), [title: string]}]

Additionally :
- if no title is given, use the generic "Group n", with n as group index.
- for options if no label is given, use value as label

-> Now only filters the options to select if not all them have to be selected. This means to select all should be faster when there is no filter used.

-> improved performances and fixed the bug where the user couldn't deselect all in filtered mode
-> added the class multiselect-item to all plugin-specific items
-> fixed an incorrect CSS selector
Signed-off-by: Tyf0x <Tyf0x@users.noreply.github.com>