1.2.6 release preparations

[akarnokd]

Version 1.2.6 - February 3, 2017 (Maven)

Documentation

• Pull 5000: Add which are the other stardard methods of create
• Pull 5007: update sample(time) diagram to indicate emission of last
• Pull 5048: Improve the javadoc of BehaviorSubject

Bugfixes

• Pull 5030: fix groupBy consuming the upstream in an unbounded manner

[akarnokd]

Closing via 1.2.6.