Desktop mode fixes

* Fix: serbanghita#857 and serbanghita#876 serbanghita#885
* fixes chrome on ios requesting desktop site (see serbanghita#857) serbanghita#883

* Added new devices sent by the users.

* fix php deprecated warning when passing null as subject in preg_match() (serbanghita#879)
* php deprecated warning when passing null as subject in preg_match()
* Fix the license file so Github can pick it up in the UI (serbanghita#861) - moved contributing section to CONTRIBUTING.md

PHP 5.x compatible release

* Added Nexus test suite (serbanghita#581)
* Add Samsung SM-G892A, SM-A530F (serbanghita#834)
* Add Xiaomi phone model (serbanghita#841)
* Add Xperia XZ serials (serbanghita#816)
* Added PhpDoc tags to help autocomplete magic calls in IDEs (serbanghita#768)
* Added script to generate methods names in PHPDoc
* New tablets (from Anne Jan) (serbanghita#851)
* Samsung Tab A7 SM-T500 not recognized as tablet (serbanghita#853)

* Samsung Galaxy Tab S7+ detected as Phone instead of Tablet type: ne…

…w User-Agent strings (serbanghita#850)

* Google Pixel should have own category status: pending research type: new User-Agent strings (serbanghita#815)
* Edge on iOS 12 is detected as Safari type: bug type: new User-Agent strings (serbanghita#764)
* Pixel 2 phone device mis-detected as Galapad tablet device type: bug type: new User-Agent strings (serbanghita#761)

Huawei AspiegelBot type: new User-Agent strings serbanghita#835

Two Samsung tablets id as phones type: new User-Agent strings serbanghita#846
Add Sailfish OS and Sailfish Browser to the detection list and tests serbanghita#784
Samsung tablets type: new User-Agent strings serbanghita#81
3rd generation iPad Pro. and it returns this is a computer type: new User-Agent strings serbanghita#827
WebP image support status: invalid type: question serbanghita#828
Fixed PHP 7.4: Trying to access array offset on value of type null  PHP7 type: bug serbanghita#830
Add new SM-G981B Samsung phone user-agent type: new User-Agent strings type: question serbanghita#836
Update Facebook Bots User Agents area: Documentaion serbanghita#837
Detecting desktop version in IOS? type: question serbanghita#845
xiaomi 8pro not detected as mobile status: invalid serbanghita#849

https://github.com/serbanghita/Mobile-Detect/milestone/26

Sony Xperia Z4 Tablet SGP771 is not detected as tablet (serbanghita#753)

Google Pixel 2 is detected as tablet (serbanghita#750)
Samsung GT-P5100 is detected as mobile (serbanghita#743)
Chrome 66 detected as Opera (serbanghita#738)
Mediacom tablets are not parsed as tablets (serbanghita#733)
Onda V10 tablet is detected as phone (serbanghita#729)
Lenovo Tab2 TB2-X30L is detected as phone (serbanghita#725)

New tablets and devices from users.

Added missing samsung tablet SM-T585 (serbanghita#712)

Lenovo Tab4 10 tablet is detected as phone (serbanghita#716)
New 3rd party module (serbanghita#714)
HUAWAI P8 phone recognized as UnknownTablet (serbanghita#711)
Asus Zenpad 8.0 (P024) should be a tablet (serbanghita#709)
Reorganizing the PHPCS rules for 2.x
Reorganized text. Added new info about desktops

Add Lenovo Mobiles (serbanghita#706)

Tablets of brand bq: regexp causes Catastrophic backtracking.(serbanghita#605)
Pixel phone support (serbanghita#610, serbanghita#611)
Moto X 2nd Gen (serbanghita#612, serbanghita#613)
Lenovo Tab3 8 Plus TB-8703F not detected as tablet (serbanghita#704)
AppleCoreMedia user agent on iPhone and iPad devices
is not recognized as iOS device when the client is requesting html5 video data (serbanghita#620)
Maybe inconsistency regarding "UC Browser" (serbanghita#451)
Use PHPUnit\Framework\TestCase instead of PHPUnit_Framework_TestCase (serbanghita#702)