Gruntfile: Restructuring.

Gruntfile: Restructuring.

Structure:
----------

Gruntfile.js:
	- configuration of basic environment;
	- loading files with more specific options;
	- loading tasks.

Grunt/options/*.js:
	- configuration options split by target.

Grunt/options/browsers.json:
	- browsers used as customLaunchers for karma.

Grunt/plugins/*:
	- plugins used in/by the grunt tasks.

Grunt/tasks/*:
	- registration of tasks.

Notable changes:
----------------

Gruntfile API:

- renamed "all" and "default" builds to the more clear "compat";
- new "travis" task, takes care of travis specific stuff;
- new "test" task, runs all tests (including server tests);
- new "default" task, runs either the "travis" or "test" task.

Other changes:

- built files now end up in a "build" directory (or "dist", of course);
- removed server-tests.js in favour of grunt-mocha-test package;
- updated the browser list (most notably: added edge);
- updated .travis.yml to use updated browser list;
- updated .travis.yml to use new "compat" build, instead of "default";
- moved syn karma-plugin into Grunt directory;
- updated and cleaned up .gitignore;
- removed no longer used packages from .package.json;
- updated README.md (some parts were actuall already out of date).