New url session handler (#932)

* Added rewritten NSUrlSessionHandler that handles memory better

This is a rewrite of the ModernHttpClient version of NSUrlSessionHandler, it has better handling for memory that provides a more consistant memory footprint. It accomplishes this by using NSInputStream for requests, and reading and disposing directly from NSData instead of transitioning the NSData to a byte[] array.

* Try to fix build of PR #31

* [foundation] Restore compatibility with the new NSUrlSessionHandler

Mostly my comments in PR #174

* Add support for redirection [1]
* Add support for credentials [1]
* Add support for caching [2]
* Remove 2nd dictionary lookup in GetHeaderSeparator
* Avoid extraneous cast for credentialsToUse

PR 177 [3] adds tests that ensure no commits can remove, or change
default values, for handlers.

[1] breaking changes (feature, not API)
[2] breaking change (API removal)
[3] #177

* [foundation] Restore compatibility with the new NSUrlSessionHandler

Mostly my comments in PR #174

* Add support for redirection [1]
* Add support for credentials [1]
* Add support for caching [2]
* Remove 2nd dictionary lookup in GetHeaderSeparator
* Avoid extraneous cast for credentialsToUse

PR 177 [3] adds tests that ensure no commits can remove, or change
default values, for handlers.

[1] breaking changes (feature, not API)
[2] breaking change (API removal)
[3] #177

* Try to fix build of PR #31

* prevent DEADLOCK in UI code

* Added ConfigureAwait(false) to Task.Delay to prevent DEADLOCK when the stream is being awaited on the UI thread

* added a few more ConfigureAwait(false) statments that were missed on first pass

* Fix some small style issues.

* Set the default value of AllowAutoRedirect to true.

.gitmodules

@@ -22,10 +22,6 @@
 	path = external/opentk
 	url = ../../mono/opentk.git
 	branch = master
-[submodule "external/ModernHttpClient"]
-	path = external/ModernHttpClient
-	url = ../../xamarin/ModernHttpClient.git
-	branch = master
 [submodule "external/Xamarin.MacDev"]
 	path = external/Xamarin.MacDev
 	url = ../../xamarin/Xamarin.MacDev

Make.config

@@ -222,7 +222,6 @@ MONOTOUCH_DIALOG_PATH=$(TOP)/external/MonoTouch.Dialog
 TOUCH_UNIT_PATH=$(TOP)/external/Touch.Unit
 NUNITLITE_PATH=$(TOP)/external/mono/external/nunit-lite
 OPENTK_PATH=$(TOP)/external/opentk
-MODERNHTTPCLIENT_PATH=$(TOP)/external/ModernHttpClient
 XAMARIN_MACDEV_PATH=$(TOP)/external/Xamarin.MacDev
 GUI_UNIT_PATH=$(TOP)/external/guiunit
 MACCORE_PATH=$(TOP)/../maccore

mk/versions.mk

@@ -64,7 +64,6 @@ $(eval $(call CheckSubmoduleTemplate,fsharp,FSHARP))
 $(eval $(call CheckSubmoduleTemplate,MonoTouch.Dialog,MONOTOUCH_DIALOG))
 $(eval $(call CheckSubmoduleTemplate,Touch.Unit,TOUCH_UNIT))
 $(eval $(call CheckSubmoduleTemplate,opentk,OPENTK))
-$(eval $(call CheckSubmoduleTemplate,ModernHttpClient,MODERNHTTPCLIENT))
 $(eval $(call CheckSubmoduleTemplate,Xamarin.MacDev,XAMARIN_MACDEV))
 $(eval $(call CheckSubmoduleTemplate,guiunit,GUI_UNIT))