Auto prefix for plugin functions

YOu no longer have to prefix all functions in a plugin with the plugin
name (linter_onSave). This will now be done automatically using lua's
setfenv. When passing a function as a callback to a editor function,
make sure to prefix the plugin name (linter.onExit, or go.goimports) so
that micro knows which plugin to call the function from.

runtime/plugins/go/go.lua

@@ -5,20 +5,20 @@ if GetOption("gofmt") == nil then
     AddOption("gofmt", true)
 end
 
-MakeCommand("goimports", "go_goimports")
-MakeCommand("gofmt", "go_gofmt")
+MakeCommand("goimports", "go.goimports")
+MakeCommand("gofmt", "go.gofmt")
 
-function go_onSave()
+function onSave()
     if CurView().Buf.FileType == "Go" then
         if GetOption("goimports") then
-            go_goimports()
+            goimports()
         elseif GetOption("gofmt") then
-            go_gofmt()
+            gofmt()
         end
     end
 end
 
-function go_gofmt()
+function gofmt()
     CurView():Save()
     local handle = io.popen("gofmt -w " .. CurView().Buf.Path)
     local result = handle:read("*a")
@@ -27,16 +27,16 @@ function go_gofmt()
     CurView():ReOpen()
 end
 
-function go_goimports()
+function goimports()
     CurView():Save()
     local handle = io.popen("goimports -w " .. CurView().Buf.Path)
-    local result = go_split(handle:read("*a"), ":")
+    local result = split(handle:read("*a"), ":")
     handle:close()
 
     CurView():ReOpen()
 end
 
-function go_split(str, sep)
+function split(str, sep)
     local result = {}
     local regex = ("([^%s]+)"):format(sep)
     for each in str:gmatch(regex) do