tosmabru detector for vlatai

I added a simple PEG rule to detect tosmabru. Then I lied to vlatai (pretending "tosmabru" is a JVS valsi type) so that it can detect them.

Sample output:

    seas491:camxes-py alex$ ./vlatai.py bauskepre
    tosmabru
    seas491:camxes-py alex$ ./vlatai.py banskepre
    lujvo