Formatting fix
Fix detection of netrw buffers

How long has this been broken?
Enable folding in :Gstatus
Fix some typos
Improve cmd.exe shell escaping
Fix commit editing on Windows

Closes #120.
Fix Windows escaping on latest 7.3 patches
Add fugitive#head() and fugitive#repo().head()

fugitive#head() returns the name of the current branch. If the current
HEAD is detached, fugitive#head() will return the empty string, unless
the optional 'len' argument is given, in which case the hash of the
current HEAD will be truncated to 'len' characters.

This makes should make life easier for people who don't want to use the
default provided by fugitive#statusline()
Leverage #head() in #statusline()
Support submodules on 1.7.10

In 1.7.10, the git-file switched from using an absolute to a relative
path.  Treat any path starting with "." as relative.  (A more robust
check for a relative path is more complicated than looking for a leading
slash because of Windows.)

Closes #201.
Support relative core.worktree

This is based on Chen Mulong's implementation in #204, but uses the same
relative path check as a8d450fcfe198d1a09676da0f98b47096db6d3fd, for
better Windows support.
Fix erroneous check for //objects

This was particularly detrimental on Windows, where it caused a slow
network lookup.

Closes #210.
Override 'shellslash' for external Windows command

With 'shellslash' set, tempname() returns a filename with forward
slashes, which trips up the type command if we don't translate to
backslashes first.

Fixes half of #212.
Add maps for resizing blame window
Follow symlinks

Previously, symlinks were not resolved. Thus, symlinks outside a git
directory would have no git dir even if they linked to a file in a git
directory.
Show diff from :Gstatus interally

When pressing enter on a header in :Gstatus, use :Git! rather than :Git
to show the diff.

Closes #208.
Re-enable editing files named index

This is a crude hack.  Watch for edge cases.

Closes #205.
Fix :Glog on Windows

Closes #199.
Revert "Follow symlinks"

This reverts commit 57af9b98cffbb5030b93eab8c26cb19f7f1f2ea6, which was
pushed by accident.
Don't activate maps without b:git_dir

Closes #227.