huge refactor

- extendable backends
- better project structure
- better cli interface

backends/interface.go

@@ -0,0 +1,19 @@
+package backends
+
+import (
+	"net/http"
+
+	"github.com/castawaylabs/cachet-monitor/monitors"
+)
+
+type BackendInterface interface {
+	Ping() error
+	Tick(monitor monitors.MonitorInterface, status monitors.MonitorStatus, errs []error, lag int64)
+	SendMetric(monitor monitors.MonitorInterface, lag int64) error
+	UpdateMonitor(monitor monitors.MonitorInterface, status, previousStatus monitors.MonitorStatus, errs []error) error
+	NewRequest(requestType, url string, reqBody []byte) (*http.Response, interface{}, error)
+
+	Describe() []string
+	Validate() []string
+	ValidateMonitor(monitor *monitors.AbstractMonitor) []string
+}