[FEATURE] Auto newline in align environment

[jtagrgh]

Description of the Problem

It would be neat if inside an align environment return would automatically end the line with \\ and start the next line with &= situated at the same place as the preceding line.

Description of the Solution

If there's currently no way to do this I could give a go at it.

Additional

[isaec]

I bet you could do this with a really evil completion like "nextstep", not sure if the perf would be a problem though.