chore(jasmine_syntax): use the guinness testing library instead of jasmine_syntax

Replace the jasmine syntax implemented by jasmine_syntax.dart and _specs.dart with Guinness:
- remove jasmine_syntax.dart
- update _specs.dart to use guinness instead of jasmine_syntax.dart
- change karma config files to initialize guinness
- replace all references to jasmine with guinness

Closes #549

Closes #994

Conflicts:
	pubspec.yaml