ibus-daemon, better NERDTree mappings, mpdconf settings

Start ibus-daemon automatically at login, using .xsessionrc
Edited NERDTree mappings to start vim-startify at start. Also, using
Ctrl-D mapping earlier was the stupidest thing ever.
Misc settings to .mpdconf

Signed-off-by: Thameera Senanayaka <thameera123@gmail.com>