Streamsx-jms

- Resolve single attribute issue for message class text (issue 22):
For message class 'text' to access the attribute to read/store the text
message in, the JMS operators now use zero index if attached tuple has
just one single attribute or otherwise determines the attribute's index
for the attribute name defined in the native schema.

Changes since ...:

- This is the first release after splitting the Message toolkit's JMS functionality into a toolkit of its own. This release here is functionally equivalent to [streamsx.messaging v5.4.1](https://github.com/IBMStreams/streamsx.messaging/releases/tag/v5.4.1). Only message IDs have been taken from a new range. This is the foundation to modernize the JMS integration into IBM Streams.