Include the file path in error messages when running external files

Should hopefully fix sonic-pi-net#2336

app/server/ruby/bin/sonic-pi-server.rb

@@ -284,7 +284,7 @@
 
   # read in init.rb if exists
   if File.exists?(init_path)
-    sp.__spider_eval(File.read(init_path), silent: true)
+    sp.__spider_eval(File.read(init_path), path: init_path, silent: true)
   else
     begin
     File.open(init_path, "w") do |f|

app/server/ruby/lib/sonicpi/lang/core.rb

@@ -463,7 +463,7 @@ def with_swing(*args, &blk)
       def run_file(path)
         path = File.expand_path(path.to_s)
         raise IOError, "Unable to run file - no file found with path: #{path}" unless File.exist?(path)
-        __spider_eval(File.read(path))
+        __spider_eval(File.read(path), path: path)
       end
       doc name:           :run_file,
           introduced:     Version.new(2,11,0),

app/server/ruby/lib/sonicpi/runtime.rb

@@ -840,11 +840,15 @@ def __spider_eval(code, info={})
             if line
               line = line.to_i
 
-              # TODO: Remove this hack when we have projects
-              w = info[:workspace]
-              w = normalise_buffer_name(w)
-              w = "buffer #{w}"
-              # TODO: end of hack
+              # If a filepath is given, use it; otherwise use the buffer name
+              w = ""
+              if (info[:path])
+                w = info[:path]
+              else
+                w = info[:workspace]
+                w = normalise_buffer_name(w)
+                w = "buffer #{w}"
+              end
 
               err_msg = "[#{w}, line #{line}] \n #{message}"
               error_line = code.lines.to_a[line - firstline] ||  ""