Add support for computed static mutator class methods
Disallow parenthesis in patterns

Fixes #155
Revert "Merge branch 'check-lval-paren-expressions' of https://github.com/sebmck/acorn"

This reverts commit c8d701914832367e3cc6f570f8da9e6096d26eef, reversing
changes made to 0f40710d6a6c846d613764f314e9fb38c247e471.
Merge branch 'patch-1' of https://github.com/RReverser/acorn