[Breaking] Change all time input parameters to milliseconds. (#78)

Changes all functions that accept a time parameter to use milliseconds instead of seconds.

* Adds duration input to NimBLEDevice::startAdvertising and NimBLEServer::startAdvertising.

src/NimBLEScan.cpp

@@ -302,7 +302,7 @@ bool NimBLEScan::isScanning() {
 
 /**
  * @brief Start scanning.
- * @param [in] duration The duration in seconds for which to scan.
+ * @param [in] duration The duration in milliseconds for which to scan.
  * @param [in] scanCompleteCB A function to be called when scanning has completed.
  * @param [in] is_continue Set to true to save previous scan results, false to clear them.
  * @return True if scan started or false if there was an error.
@@ -319,10 +319,6 @@ bool NimBLEScan::start(uint32_t duration, void (*scanCompleteCB)(NimBLEScanResul
     if(duration == 0){
         duration = BLE_HS_FOREVER;
     }
-    else{
-        // convert duration to milliseconds
-        duration = duration * 1000;
-    }
 
     // Set the flag to ignore the results while we are deleting the vector
     if(!is_continue) {