[WIP] Introduced component installer. jQuery now is auto-updated to the newest 1.X.X versions. Closes #826.

Note: Because jQuery dropped several functions from 1.8 to 1.9, the jquery migrate plugin is included every time jquery is included.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | --
| Fixed tickets | #826
| License       | MIT
| Doc PR        | --

This is actually working for me, but I'd like to test this with some other modules. Which modules are jquery-based already?