New Rule: no-constant-condition (fixes #621)
New Rule: no-constant-condition
 - removed SwitchStatement discriminant check
 - removed AssignmentExpression with right Identifier
 - fixed copy paste error
 - added DoWhileStatement, ForStatement
based on discussion: https://github.com/eslint/eslint/pull/624
(fixes #621)
Merge pull request #624 from makepanic/621-no-constant-condition

New Rule: no-constant-condition (fixes #621)