test: Streamline test suite a little

This change aims to streamline the integrationtest suite and reduce friction when running (parts of) test suites.

Changes:
- add `test-testname` to makefile to easily run one suite
- made skipping tests first class citizen in test.sh (all available testsuites and the reasons they are skipped are now better exposed and discovered)
- suppress some output of gotest unless there is an error
- no longer build binary for examples and gotest suites
- removed .SILENT from makefile as it being applied to only some targets makes it feel weird (I just learned about this option btw, feel free to comment on this change)
- move individual tests out of `test.sh` and into `test-misc.sh`
- introduced the concept of testsuites to `test.sh`

test/util.sh

@@ -1,3 +1,5 @@
+#!/bin/bash
+
 # common settings and functions for test scripts
 
 if [[ $(uname) == "Darwin" ]] ; then
@@ -13,3 +15,8 @@ fail_test()
 	echo "FAIL: $@"
 	exit 1
 }
+
+function run-test()
+{
+	"$@" || failures=$( [ -n "$failures" ] && echo "$failures\\n$@" || echo "$@" )
+}