Introduce nvim namespace: Move files.

Move files from src/ to src/nvim/.
- src/nvim/ becomes the new root dir for nvim executable sources.
- src/libnvim/ is planned to become root dir of the neovim library.

src/nvim/testdir/test_eval.in

@@ -0,0 +1,57 @@
+STARTTEST
+
+:e test.out
+:%d
+
+:" function name not starting with a capital
+:try
+:  func! g:test()
+:    echo "test"
+:  endfunc
+:catch
+:  $put =v:exception
+:endtry
+
+:" function name folowed by #
+:try
+:  func! test2() "#
+:    echo "test2"
+:  endfunc
+:catch
+:  $put =v:exception
+:endtry
+
+:" function name includes a colon
+:try
+:  func! b:test()
+:    echo "test"
+:  endfunc
+:catch
+:  $put =v:exception
+:endtry
+
+:" function name starting with/without "g:", buffer-local funcref.
+:function! g:Foo(n)
+:  $put ='called Foo(' . a:n . ')'
+:endfunction
+:let b:my_func = function('Foo')
+:call b:my_func(1)
+:echo g:Foo(2)
+:echo Foo(3)
+
+:" script-local function used in Funcref must exist.
+:so test_eval_func.vim
+
+:" using $ instead of '$' must give an error
+:try
+:  call append($, 'foobar')
+:catch
+:  $put =v:exception
+:endtry
+
+:1d
+:w
+:qa!
+
+ENDTEST
+