Added basic lit configuration file for running tests.
Enable houdini lit tests. Note some still fail due to Boogie
outputing absolute paths to .bpl files in error messages
Added /useBaseNameForFile command line argument. The Scanner
and Parser constructors have been modified to take an optional
argument specifying this and the ExecutionEngine passes for that
value CommandLineOptions.Clo.UseBaseNameForFileName

This option when true causes the basename of file to be used inside
created Tokens instead of what the user passed on the command line
which might be a relative or absolute path.

The motivation for adding this option is that it is needed for the
lit driven tests so that the output of Boogie can be reliably checked.
Pass -useBaseNameForFileName option to Boogie when running tests.
This is needed because the expected test output contains just the basename
of the .bpl files in error messages but lit passes an absolute path
to Boogie so without this option error messages would contain absolute
paths which would cause the tests to fail.

Now all the houdini tests pass when driven by lit.
Add lit.local.cfg that instructs not to run any tests in this
directory or its subdirectories. The test in this directory
is pointless because we will run it later on anyway!

When we migrate to lit this test directory should be removed
Converted textbook tests to lit tests.
Enabled most of the name resolution lit tests. They don't all pass
yet due to a bug in -useBaseNameForFileName.
Teach the ExecutionEngine to respect the -useBaseNameForFileName commandline
option when reporting the number of errors.
Enabled lit tests for test1/ directory
Bizarely Array.bpl does not pass on Windows. This will be fixed soon.
For lit tests running on Windows pass /W flag to the fc tool
so that all whitespace (including mismatching line endings due
to DOS vs UNIX) are ignored. This fixes the test1/Arrays.bpl
test under Windows. It's quite suprising this issue didn't
come up earlier.
Enabled VC Generation lit tests.
Enable the VCVariety.BlockNested tests as lit tests.
Enabled tests for types introduced in Boogie2 as lit tests.
Enabled "Verify Boogie 2" lit tests. Note the following tests fail
because they were never properly tested in the the old testing
infrastructure.

test21/Maps2.bpl
test21/test3_AddMethod_conv.bpl
Enable the Constant propagation tests as lit tests.
For lit test infrastructure, disable running tests in

AbsHoudini/
test17/
z3api/

because the alltests.txt claims they are "Postponed"
Enable Linear inequality lit tests.
Enable "abstract domain of intervals" lit tests.
Enable "SLAM example" lit tests.
Enable "error messages for failing asserts vs. loop invariants" lit tests.