Test an initial submodule update, where we are trying to checkout
the submodule for the first time, and placing a file within the
submodule working directory with the same name as the submodule
(and consequently, the same name as the repository itself).

A corpus of files checked out with Git (Linux, 1.9.1) to ensure that
produce identical data when checking out using a CRLF filter.

A corpus of files checked out with Git for Windows (2.4.1.windows.1)
to ensure that we produce identical data when checking out using a
CRLF filter.

Include the UTF8 and UTF8 BOM tests in the master crlf test
branch for completeness.

Include additional test data for CRLF tests: files with mixed
line endings and binary files.

A remote's URLs are now modified according to the url.*.insteadOf
and url.*.pushInsteadOf configurations. This allows a user to
replace URL prefixes by setting the corresponding keys. E.g.
"url.foo.insteadOf = bar" would replace the prefix "bar" with the
new prefix "foo".

The .gitattributes cache should not reload .gitattributes in the
middle of checking out, only between checkout operations.  Otherwise,
we'll spend all our time stat'ing and read'ing the gitattributes.

Symbolic links that abuse case insensitivity to write into .git.