Increased testing to include geometries that can't be fully tested

This is primarily to get better test coverage over devices with very
large erase/prog/read sizes. The unfortunate state of the tests is
that most of them rely on a specific block device size, so that
ENOSPC and ECORRUPT errors occur in specific situations.

This should be improved in the future, but at least for now we can
open up some of the simpler tests to run on these different
configurations.

Also added testing over both 0x00 and 0xff erase values in emubd.

Also added a number of small file tests that expose issues prevalent
on NAND devices.

.travis.yml

@@ -23,8 +23,20 @@ script:
   - make test QUIET=1 CFLAGS+="-DLFS_BLOCK_COUNT=1023 -DLFS_LOOKAHEAD_SIZE=256"
 
   - make clean test QUIET=1 CFLAGS+="-DLFS_INLINE_MAX=0"
+  - make clean test QUIET=1 CFLAGS+="-DLFS_EMUBD_ERASE_VALUE=0xff"
   - make clean test QUIET=1 CFLAGS+="-DLFS_NO_INTRINSICS"
 
+  # additional configurations that don't support all tests (this should be
+  # fixed but at the moment it is what it is)
+  - make test_files QUIET=1
+        CFLAGS+="-DLFS_READ_SIZE=1 -DLFS_BLOCK_SIZE=4096"
+  - make test_files QUIET=1
+        CFLAGS+="-DLFS_READ_SIZE=\(2*1024\) -DLFS_BLOCK_SIZE=\(64*1024\)"
+  - make test_files QUIET=1
+        CFLAGS+="-DLFS_READ_SIZE=\(8*1024\) -DLFS_BLOCK_SIZE=\(64*1024\)"
+  - make test_files QUIET=1
+        CFLAGS+="-DLFS_READ_SIZE=11 -DLFS_BLOCK_SIZE=704"
+
   # compile and find the code size with the smallest configuration
   - make clean size
         OBJ="$(ls lfs*.o | tr '\n' ' ')"