Missing methods/patterns

[d3vp]

So far I have added the following things I found missing in sc3:

• method: Env.delay
• class Pgauss(ValuePattern)

Is there any alternative to delay?

[smrg-lm]

Pgauss is missing along with the patterns in RandomDistPatterns.sc which are part of the main library. It is a TODO, it could go in sc3/seq/patterns/valuepatterns.py under a ### Random distribution patterns ### section at the end.

I don't remember why I didn't transcribe Env.delay, it might be because it's an instance method that returns a new modified instance and was considered sugar. The problem with that kind of methods is that they may pollute the API with particular use cases.