Update memo entries

[gam6itko]

Features

add

• declare(strict_types=1); for all files
• Ability to add, edit and delete memo entries for VFP, Foxpro and DBase7.
• All setters return $this.
• RecordInterface::get('name')
• RecordInterface::set('name', $value) methods
• WritableTable::save you should use it to save table changes.

changes

• Getter for type D (Date) returns date string in 'Ymd' format instead of timestamp.
• VisualFoxproRecord::getDateTime returns object of \DateTimeInterface instead of timestamp.

deprecations

• RecordInterface::getObject
• RecordInterface::setObject
• Setters like Record::setType. Use set('name', $value) method instead.
• Getters like Record::getType. Use get('name') method instead.
• WritableTable::openWrite. Method is no longer needed.

fixes

• Can't add/update memo field (long text) #91
• Missing end-of-file marker #43