Add BaiduMap v4.0.0 support - For merging

[droneboost]

@ne0fhyk

I've squashed commit histories in this PR, would you please check and approve merge?

Thanks.

[m4gr3d]

@droneboost looks good to go!

[droneboost]

@ne0fhyk, thanks for merging.

[Linjieqiang]

@Tanson Thanks.Also thanks @droneboost code for baidu map.

[droneboost]

@Linjieqiang, Thanks! We are looking forward to see your PR with more new feature for CN maps. Let's make Tower a better GCS App together.

[m4gr3d]

@droneboost I'm preparing to release the first beta for version 4.0. How do I go about updating the baidu map developer key?

[droneboost]

@ne0fhyk , do you have a Baidu developer account? If don't have, please register an account on following links:

https://passport.baidu.com/v2/?reg&tpl=newdev&u=http://developer.baidu.com/

[m4gr3d]

@droneboost I'm unable to register for an account since it requires a chinese mobile phone number. Any suggestions?

[droneboost]

@ne0fhyk , seems Chinese mobile phone number is a prerequisite of BD developer account, for the time being, I think I can apply a map API key for you for testing, if you share your android SDK sha1 signature on your build machine to me, please check this page: http://lbsyun.baidu.com/index.php?title=androidsdk/guide/key

[m4gr3d]

@droneboost sounds good. Can you send me your email address, so I can email you the sha1 fingerprint. You can find my email address on my github profile. I'm unable to find your email on github though.

In addition, am I able to release the app with the map API key you will send?

[droneboost]

@ne0fhyk , my email : fcao2008@gmail.com, I've sent you an email.

In addition, am I able to release the app with the map API key you will send?

Sure! Before you are able to get your own Baidu developer account, I'm glad to maintain the baidu map API key for Tower.