mdhelp: add epg_grabber_config doc, update cron doc + screenie

docs/class/epg_grabber_config.md

@@ -0,0 +1,22 @@
+This tab is used to configure the Electronic Program Guide (EPG) 
+grabbing capabilities. Tvheadend supports a variety of different EPG 
+grabbing mechanisms. These fall into 3 broad categories, within which 
+there are a variety of specific grabber implementations.
+
+!['EPG Grabber Configuration'](static/img/doc/epggrabberconfig.png)
+
+---
+
+###Menu Bar/Buttons
+
+The following functions are available:
+
+Button                      | Function
+----------------------------|-------------------
+**Save**                    | Save any changes made to the tab.
+**Undo**                    | Revert any changes made since the last save.
+**Trigger OTA EPG Grabber** | Force an immediate tune to the OTA EPG mux(es) to request EPG updates.
+
+<tvh_include>inc/common_button_table_end</tvh_include>
+
+---

docs/property/cron.md

@@ -1,21 +1,17 @@
 :
 Example : every day at 2am is : `0 2 * * *` 
 
-`┌───────────── min (0 - 59)` 
-
-`│ ┌────────────── hour (0 - 23)` 
-
-`│ │ ┌─────────────── day of month (1 - 31)` 
-
-`│ │ │ ┌──────────────── month (1 - 12)` 
-
-`│ │ │ │ ┌───────────────── day of week (0 - 6) (0 to 6 are Sunday to Saturday, or use names; 7 is Sunday, the same as 0)` 
-
-`│ │ │ │ │` 
-
-`│ │ │ │ │` 
-
-`* * * * *` 
+```
+# * * * * *
+# ┬ ┬ ┬ ┬ ┬
+# │ │ │ │ │
+# │ │ │ │ │
+# │ │ │ │ └───── day of week (0 - 6 or Sunday - Saturday)
+# │ │ │ └────────── month (1 - 12)
+# │ │ └─────────────── day of month (1 - 31)
+# │ └──────────────────── hour (0 - 23)
+# └───────────────────────── min (0 - 59)
+```
 
 You cannot use non-standard predefined scheduling definitions for this 
 field.

src/epggrab.c

@@ -243,10 +243,14 @@ epggrab_class_ota_cron_notify(void *self, const char *lang)
   epggrab_ota_set_cron();
 }
 
+CLASS_DOC(epg_grabber_config)
+PROP_DOC(cron)
+
 const idclass_t epggrab_class = {
   .ic_snode      = &epggrab_conf.idnode,
   .ic_class      = "epggrab",
-  .ic_caption    = N_("EPG grabber configuration"),
+  .ic_caption    = N_("EPG Grabber Configuration"),
+  .ic_doc        = tvh_doc_epg_grabber_config_class,
   .ic_event      = "epggrab",
   .ic_perm_def   = ACCESS_ADMIN,
   .ic_changed    = epggrab_class_changed,
@@ -320,6 +324,7 @@ const idclass_t epggrab_class = {
                    "The default cron triggers the internal grabbers "
                    "daily at 12:04 and 00:04. See Help on how to define "
                    "your own."),
+      .doc    = prop_doc_cron,
       .off    = offsetof(epggrab_conf_t, cron),
       .notify = epggrab_class_cron_notify,
       .opts   = PO_MULTILINE | PO_ADVANCED,
@@ -342,6 +347,7 @@ const idclass_t epggrab_class = {
                    "The default cron triggers the Over-the-air "
                    "grabber daily at 02:04 and 14:04. See Help on how "
                    "to define your own."),
+      .doc    = prop_doc_cron,
       .off    = offsetof(epggrab_conf_t, ota_cron),
       .notify = epggrab_class_ota_cron_notify,
       .opts   = PO_MULTILINE | PO_ADVANCED,