Support missing api

[ki4070ma]

The problem

There are some missing api supports on python client

Example: #351

How to extract missing api support

$cd /path/to/appium/commands-yml/commands
$find . -name "*yml" | while read FILE; do if [ `grep "python: false" $FILE | wc -l` = 1 ];then echo "****" && echo $FILE && grep python $FILE; fi; done
-> And checked if there are apis in python-client.

[ki4070ma]

Missing apis

• GSM Signal
  • http://appium.io/docs/en/commands/device/network/gsm-signal/
• GSM Call
  • http://appium.io/docs/en/commands/device/network/gsm-call/
• GSM Voice
  • http://appium.io/docs/en/commands/device/network/gsm-voice/
• Get System Bars
  • http://appium.io/docs/en/commands/device/system/system-bars/
• Get Performance Data
  • http://appium.io/docs/en/commands/device/performance-data/get-performance-data/
• Get Performance Data Types
  • http://appium.io/docs/en/commands/device/performance-data/performance-data-types/
• Emulate power capacity
  • http://appium.io/docs/en/commands/device/emulator/power_capacity/
• Emulate power state
  • http://appium.io/docs/en/commands/device/emulator/power_ac/

Will not support

• Toggle Data
  • http://appium.io/docs/en/commands/device/network/toggle-data/
  • Low priority since this API does not work for Android API level 21+
• Toggle Airplane Mode (works only API below 24)
  • http://appium.io/docs/en/commands/device/network/toggle-airplane-mode/
  • Reason > Failed test case when calling toggle_airplane_mode on AndroidP appium#12557