Add null check for LockedAllocator.free and realloc. See #672.
Remove debug CT message.
Add basic attribute based validation for vibe.web.web and some doc comments.
Change the vibe.web.web validation framework to be type based instead of UDA based.
Improve the test for the new std.concurrency interop extensions. See #703.

Since this isn't merged for DMD 2.066 alpha yet, and explicit check for the presence of "Scheduler" was added (see #703). The "newStdConcurrency" enum was also put into an own module to sidestep cyclic module reference issues.
Obscure workaround for Travis-CI build failure.
[Trivial] Update gitignore
Merge pull request #704 from BoapNet/upd-gitignore

[Trivial] Update gitignore
Remove deprecated features.