Streaming I/O and support of named pipes (#570)

* added streaming i/o for scripting, and a byteutil.get_size function

* added i/o stream class, also added named pipes support on lua side via ffi

* added constant file.named_pipes_prefix

* added buffered and yield modes for io_stream

* added new time function for work with UTC - utc_time, utc_offset, local_time

* docs updated

* constant pid moved to os.pid

* now gmtime_s and localtime_s used only in windows

res/scripts/stdlib.lua

@@ -317,10 +317,30 @@ entities.get_all = function(uids)
         return stdcomp.get_all(uids)
     end
 end
+
 local bytearray = require "core:internal/bytearray"
+
 Bytearray = bytearray.FFIBytearray
 Bytearray_as_string = bytearray.FFIBytearray_as_string
 Bytearray_construct = function(...) return Bytearray(...) end
+
+file.open = require "core:internal/stream_providers/file"
+file.open_named_pipe = require "core:internal/stream_providers/named_pipe"
+
+if ffi.os == "Windows" then
+    ffi.cdef[[
+    unsigned long GetCurrentProcessId();
+    ]]
+    
+    os.pid = ffi.C.GetCurrentProcessId()
+else
+    ffi.cdef[[
+    int getpid(void);
+    ]]
+
+    os.pid = ffi.C.getpid()
+end
+
 ffi = nil
 
 math.randomseed(time.uptime() * 1536227939)
@@ -473,6 +493,7 @@ function __vc_on_world_quit()
     _rules.clear()
     gui_util:__reset_local()
     stdcomp.__reset()
+    file.__close_all_descriptors()
 end
 
 local __vc_coroutines = {}
@@ -629,4 +650,4 @@ function dofile(path)
         end
     end
     return _dofile(path)
-end
+end