Fix incorrect g:terminal_color_* variables for NeoVim.

Fixes https://github.com/lifepillar/vim-solarized8/issues/46.

templates/_neovim_light.colortemplate

@@ -0,0 +1,27 @@
+# vim: ft=colortemplate fdm=marker
+
+verbatim
+if has('nvim')
+endverbatim
+TermCursor        -> Cursor
+TermCursorNC         base03            base01
+verbatim
+let g:terminal_color_0='@guibase2'
+let g:terminal_color_1='@guired'
+let g:terminal_color_2='@guigreen'
+let g:terminal_color_3='@guiyellow'
+let g:terminal_color_4='@guiblue'
+let g:terminal_color_5='@guimagenta'
+let g:terminal_color_6='@guicyan'
+let g:terminal_color_7='@guibase02'
+let g:terminal_color_8='@guibase3'
+let g:terminal_color_9='@guiorange'
+let g:terminal_color_10='@guibase1'
+let g:terminal_color_11='@guibase0'
+let g:terminal_color_12='@guibase00'
+let g:terminal_color_13='@guiviolet'
+let g:terminal_color_14='@guibase01'
+let g:terminal_color_15='@guibase03'
+endif
+endverbatim
+