feat($http): add support for aborting via timeout promises

If the timeout argument is a promise, abort the request when it is resolved.
Implemented by adding support to $httpBackend service and $httpBackend mock
service.

This api can also be used to explicitly abort requests while keeping the
communication between the deffered and promise unidirectional.

Closes #1159
chore(ngdocs): move angular-bootstrap.js to be generated only inside the docs and remove from the build process
fix(ngdocs): provide test code for syntax links in docs and fix the syntax directive for IE8
fix(ngdocs): fix gen_docs.sh
chore(package.json): use `devDependencies` instead of `dependencies`
chore(package.json): kill version.yaml in favor of package.json

all versioning info is now in package.json and that's where the build scripts read it from
chore(version.js): remove unused/obsolete script
docs(guide/type): remove empty "Type" page in guide

Closes #1316
doc($compile): clarify compile function return value

If a compile function (within a directive) returns a function, it is a
post-link function.

Closes: #2713
docs(ngScenario): provide examples for element(...).query(fn)

element(selector, label).query(fn) is a very useful function, yet barely
explained. The developer guide should show how this function can be used
to conditionally execute behavior and assertions.
docs(tutorial): fix the float issue with the improve docs button
docs(Angular.js): add missing @returns to extend()
docs(CHANGELOG.md): release notes for 1.1.5 and 1.0.7 releases
chore(release): cut the 1.1.5 triangle-squarification release
chore(release): start 1.1.6 spooky-giraffe iteration