Create basic Makefile
Makefile: Enable warnings

And fix issues in test.c.
.gitignore: Update for name changes and .o files
test: Read upto 100 MiB and operate on that

So that we can create arbitrary sized input to test with.
test: Take user supplied input
test: Remove my errexit() function
test: Reduce max read size to 32 MiB

Some platforms I'd like to test don't have enough memory to support
allocating 200 MiB but most should have enough to support allocating
64 MiB for the test.
README: Write some basic purpose and usage