Release 0.4 prediction different than previous release (under certain test case)

[channelz]

Test case 1:
Prompt : <soq> What is
Prediction : soq> What is .....

^the leading '<' is always trimmed away. Did not preform this way in the previous release.

Test case 2:
Prompt : What is
Prediction : What is ...

The prediction is as expected.

[minimaxir]

In 0.4.0 I added an lstrip param (default true) to strip whitespace from the beginning of the text: however, it appears ^\W+ is the wrong regex since it'll catch the leading <.

You can set lstrip=False to generate() for the time being but I'll add a more correct regex.