Fix mongodb 3.6 aggregate

[WebFreak001]

This PR replaces the aggregate function and adds support for options and makes MongoCursor more extensible with support for any cursors instead of only find cursors

fix #2036, fix #1718

Tested with latest MongoDB 3.2, 3.4, 3.6

[timotheecour]

also ran into #2036 but after patching this in vibe I get:

cd dub-registry
#edit dub.sdl to point to modified vibe
dub upgrade

dub build
lots of errors, eg:
../../../../.dub/packages/dub-1.3.0/dub/source/dub/commandline.d(1687,21): Error: no property 'length' for type 'GenericPath!(PosixPathFormat)'

diff --git a/dub.sdl b/dub.sdl
index c5e3e8a..784bf30 100644
--- a/dub.sdl
+++ b/dub.sdl
@@ -4,7 +4,9 @@ homepage "http://code.dlang.org/"
 authors "Sönke Ludwig" "Matthias Dondorff"
 license "GPL-3.0"

-dependency "vibe-d" version="~>0.8.0-beta"
+#dependency "vibe-d" version="~>0.8.0-beta"
+dependency "vibe-d" path="/Users/timothee/git_clone/D/vibe.d"
+
 dependency "dub" version="~>1.3.0-beta"
 dependency "userman" version="~>0.3.2"
 subConfiguration "dub" "library-nonet"
diff --git a/dub.selections.json b/dub.selections.json
index d99f989..eb9c385 100644
--- a/dub.selections.json
+++ b/dub.selections.json
@@ -4,17 +4,18 @@
                "backtrace-d": "~master",
                "botan": "1.12.9",
                "botan-math": "1.0.3",
-               "diet-ng": "1.4.3",
+               "diet-ng": "1.4.4",
                "dub": "1.3.0",
-               "eventcore": "0.8.15",
+               "eventcore": "0.8.27",
                "libasync": "0.8.3",
                "libev": "5.0.0+4.04",
                "libevent": "2.0.2+2.0.16",
-               "memutils": "0.4.9",
-               "openssl": "1.1.5+1.0.1g",
-               "taggedalgebraic": "0.10.7",
-               "userman": "0.3.7",
-               "vibe-core": "1.1.1",
-               "vibe-d": "0.8.1"
+               "memutils": "0.4.10",
+               "openssl": "1.1.6+1.0.1g",
+               "stdx-allocator": "2.77.0",
+               "taggedalgebraic": "0.10.9",
+               "userman": "0.3.8",
+               "vibe-core": "1.4.0-alpha.1",
+               "vibe-d": {"path":"../../../D/vibe.d"}
        }
 }

[WebFreak001]

@timotheecour try upgrading the dub dependency. I merged master into this now but now I get a completely unrelated error which complains about stream/vibe/stream/memory.d...

[timotheecour]

ya i got this as well, depending on how i do things:

../../../D/vibe.d/stream/vibe/stream/memory.d(56,42): Error: constructor vibe.utils.array.AllocAppender!(ubyte[], ubyte).AllocAppender.this (IAllocator alloc, ubyte[] initial_buffer = null) is not callable using argument types (IAllocator)
dmd failed with exit code 1.

[wilzbach]

That indicates that your vibe-core or vibe.d itself still uses std.experimental.allocator and not the dub package stdx-allocator.
stdx-allocator has been added to vibe.d in 0.8.3-alpha.1 and to vibe-core in 1.4.0-alpha.1 - a new release of both would make things considerably easier (see also: #2058)

[WebFreak001]

huh on the test servers it paseses so I guess it's not broken ¯\_(ツ)_/¯

[s-ludwig]

I'll have to see whether we can improve the transition from std.experimental.allocator to stdx.allocator with reasonable effort, before tagging the next release. Having to upgrade both, vibe-d and vibe-core at the same time is not really nice and also not really compatible with the intent of SemVer, even if this is private code.