rclnodejs v0.15.0

Note: v0.15.0 has been tested against ROS 2 Foxy Fitzroy Patch Release 1 by 3071fea (2020-7-21)

Feature

• multiple context support #668 #669

Bug Fix

• Use Read-write locks to protect the data shared between threads #662
• Gen 'number[] | typed-array' union in tsd files #658 #665
• fix compatibility for eloquent #666
• Align with the basic types which can be typed-arrays #670
• Fix compiling error when using Node.js v10.12.0 #678
• Fix double-free when using typed array #679
• fix use-after-free in subscription callbacks #680