First split into crockery init and crockery run

The init command creates a crockery.db file containing the domain name and
TLS keypair. The run command starts IMAP and SMTP services based on that file.

Supporting only a single domain is starting to look a bit unnecessary. We'll
see how that goes.

vendor/github.com/asdine/storm/q/regexp.go

@@ -0,0 +1,51 @@
+package q
+
+import (
+	"fmt"
+	"regexp"
+	"sync"
+)
+
+// Re creates a regexp matcher. It checks if the given field matches the given regexp.
+// Note that this only supports fields of type string or []byte.
+func Re(field string, re string) Matcher {
+	regexpCache.RLock()
+	if r, ok := regexpCache.m[re]; ok {
+		regexpCache.RUnlock()
+		return NewFieldMatcher(field, &regexpMatcher{r: r})
+	}
+	regexpCache.RUnlock()
+
+	regexpCache.Lock()
+	r, err := regexp.Compile(re)
+	if err == nil {
+		regexpCache.m[re] = r
+	}
+	regexpCache.Unlock()
+
+	return NewFieldMatcher(field, &regexpMatcher{r: r, err: err})
+}
+
+var regexpCache = struct {
+	sync.RWMutex
+	m map[string]*regexp.Regexp
+}{m: make(map[string]*regexp.Regexp)}
+
+type regexpMatcher struct {
+	r   *regexp.Regexp
+	err error
+}
+
+func (r *regexpMatcher) MatchField(v interface{}) (bool, error) {
+	if r.err != nil {
+		return false, r.err
+	}
+	switch fieldValue := v.(type) {
+	case string:
+		return r.r.MatchString(fieldValue), nil
+	case []byte:
+		return r.r.Match(fieldValue), nil
+	default:
+		return false, fmt.Errorf("Only string and []byte supported for regexp matcher, got %T", fieldValue)
+	}
+}