Ensure vim uses compatible shell

If you're using fish or some other shell, this will keep the install from failing.
Remove trailing whitespace.
Escape "*nix".
Give more robust default method for bootstrapping.
Use invhlsearch instead of nohlsearch

This command toggles the highlight state, allowing the user to turn it off and
on as desired without it automatically turning back on.

I found it very annoying that some random command would set the search pattern
to something common like `\s\+` and suddenly my entire Vim session would be
highlighted. `<leader>/` turned if off but any kind of search related motion (or
running the command again, for example) would turn it back on again.

If the user turns off search highlighting, they probably don't want it to
immediately turn back on. If they do, it's as easy as `<leader>/` again.
Add Tabularize shortcut for &
Merge pull request #257 from johntyree/tabularize_ampersand

Add Tabularize shortcut for &.
Merge pull request #256 from johntyree/invhlsearch

Use invhlsearch instead of nohlsearch
Merge pull request #232 from beyondwords/3.0

Ensure vim uses compatible shell in bootstrap
Use curl instead of wget.
Merge pull request #250 from johntyree/bootstrap

Use more robust method for bootstrapping.
symlink override

this fixes the Issue #260.
https://github.com/spf13/spf13-vim/issues/260

If a old symlink of .vimrc exists the new symlink is created by force.
Merge pull request #261 from sanitoeter/3.0

symlink override
Merge remote-tracking branch 'spf13-vim/3.0' into 3.0