Fixes Bug 1007530 - OOM signature manipulations

added processed crash transform rule (predicate):
* The OOMAllocationSize annotation is present
* The signature contains NS_ABORT_OOM, mozalloc_handle_oom, CrashAtUnhandlableOOM

added processed crash transform rule (action):

    If the OOMAllocationSize annotation is present:
        If the value is 256k or smaller (262144):
            The signature should be "OOM | Small"
        If the value is larger than 256k:
            The signature should be "OOM | Large | <C++Signature>"
    Else:
        The signature should be "OOM | Unknown | <C++Signature>"

the original unmodified signature is available as ```processed_crash.original_signature``` _iff_ the predicate succeeded.