Install YouCompleteMe

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Remove supertab.

YouCompleteMe obsoletes supertab.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
vim-slim repository moved sometime back; start tracking the new one

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Update all plugins.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Don't report untracked content in vim-powerline plugin.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>