1. Add the `MultipleStatementAlignment` sniff
    The code base basically already complies with this rule, which demands that the assignment operators for blocks of variable assignments are aligned.
    When an assignment is not in a block, there should be exactly one space between the variable and the assignment.
    Includes fixing up the code base for the very few places where the code didn't comply yet.
2. Add the `IncludingFile` sniff
    Again, the code base already complies with this rule, safe for the unit test bootstrap, in which case it is ok that the code doesn't comply.

Includes one minor consistency fix, prefixing a global constant when used with a namespace separator to indicate global namespace.