system clipboard -> vim default register

for linux, osx and windows.
follow-up for #153
Merge pull request #155 from wolfgangpfnuer/patch-3

system clipboard -> vim default register
Simplifying the register--clipboard logic 

Thanks wolfgangpfnuer for this contribution
Add symlinks to .fork files in installer
add indent_guides
Merge pull request #160 from JoveYu/3.0

add indent_guides
Fix symlink check bug in dotfiles backup.
fix the conflict of <C-u>
Merge pull request #161 from kevinwaddle/3.0

Fix symlink check bug in dotfiles backup.
Merge pull request #162 from JoveYu/3.0

fix the conflict of <C-u>
added BundleInstall to the windows installer .cmd file
add explicit .vimrc.bundles parameter to .cmd
windows xp installer .cmd

Since there is no mklink in windows XP and installing the tool that
provides this function is only possible on NTFS filesystems I created
this installer for my colleagues at work.

Probably far from a perfect solution but just so people on old XP boxes
can enjoy the awesomness easily.
Remove duplicate 'set background' from Basic

set background=dark is in General too
Merge pull request #157 from taxilian/link_fork_files

Add symlinks to .fork files in installer.. enabling fork maintainers to retain the installer
Merge pull request #168 from jhnwsk/windows-installer-fix

added BundleInstall to the windows installer .cmd file
Merge pull request #173 from naufraghi/3.0

Remove duplicate 'set background' from Basic
Fixing issue #170 (non-0 exit code on OSX)
Applied Sass filetype temporary workaround. Waiting on permanent fix to Better-CSS-Syntax-for-Vim
Merge pull request #174 from mmikitka/3.0

Applied Sass filetype temporary workaround. Waiting on permanent fix to ...