Power consumption graphs were added to ulp and wifi power save examples

Closes IDF-208

examples/system/ulp/README.md

@@ -51,3 +51,7 @@ Entering deep sleep
 Note that in one case the pulse count captured by the ULP program is 6, even though the `edge_count_to_wake_up` variable is set to 10 by the main program. This shows that the ULP program keeps track of pulses while the main CPUs are starting up, so when pulses are sent rapidly it is possible to register more pulses between wake up and entry into app_main.
 
 With the default configuration (20ms ULP wakeup period), average current consumption in deep sleep mode is 16uA.
+
+## Typical current consumption
+
+![CurrentConsumption](image/ulp_power_graph.png)

examples/wifi/power_save/README.md

@@ -11,3 +11,13 @@ Power save mode only works in station mode. If the modem sleep mode is enabled,
 * Maximum modem sleep: In maximum modem sleep mode, station wakes up every listen interval to receive beacon. Broadcast data may be lost because station may be in sleep state at DTIM time. If listen interval is longer, more power is saved but broadcast data is more easy to lose. 
 
 * others: not supported yet.
+
+### Typical current consumption with management enabled
+
+![current consumption with CONFIG_PM_ENABLE enabled](image/power_save_graph.png)
+
+### Typical current consumption with management disabled
+
+![current consumption with CONFIG_PM_ENABLE disabled](image/power_save_graph_PM_disabled.png)
+
+Note that current consumption and average current are higher when disabled.