Revert "Remove checks for loaded ftplugin and indent" (#558)

Author: milanglacier

ftplugin/org.vim

@@ -1,3 +1,8 @@
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
 lua require('orgmode.config'):setup_mappings('org')
 lua require('orgmode.config'):setup_mappings('text_objects')
 

indent/org.vim

@@ -1,3 +1,8 @@
+if exists('b:did_indent')
+  finish
+endif
+let b:did_indent = 1
+
 function! OrgmodeIndentExpr()
   return luaeval('require("orgmode.org.indent").indentexpr()')
 endfunction