Instrumenting a library with fixed bytes keys causes an error

[cd1m0]

Given the following sample:

contract Foo {
        mapping (bytes19 => address) m;
        /// #if_succeeds forall(bytes19 i in m) m[i] != address(0);
        function foo() public {}
}

We get the following exception:

Error: Unknown type bytes19 in getTypeDesc
    at getTypeDesc (/home/dimo/work/consensys/scribble/dist/instrumenter/utils.js:247:11)
    at generateMapLibrary (/home/dimo/work/consensys/scribble/dist/instrumenter/custom_maps_templates.js:209:48)
    at TypesToLibraryMap.makeNew (/home/dimo/work/consensys/scribble/dist/instrumenter/instrumentation_context.js:99:68)
    at TypesToLibraryMap.get (/home/dimo/work/consensys/scribble/dist/instrumenter/utils.js:213:24)
    at interposeMap (/home/dimo/work/consensys/scribble/dist/instrumenter/custom_maps.js:203:48)
    at instrumentFiles (/home/dimo/work/consensys/scribble/dist/bin/scribble.js:165:40)
    at /home/dimo/work/consensys/scribble/dist/bin/scribble.js:642:13

The root cause is that the case for fixed bytes is missing in the getTypeDesc function. Just add that and it works

[cd1m0]

Fixed in #268