Support for video capture orientation

[ming]

Currently there is no mechanism to notify other party about new video orientation, so in this ticket, we implement a feature which allows the video sender to transmit video with the "proper" orientation at all time, i.e: head upside whatever the device orientation is. When a device orientation changes, the application can tell the library and the library will rotate the video, resize it accordingly, and insert blank/black in left+right sides. The receiver/decoder side will then receive the video in the correct orientation, nothing to do on the decoder side.

The feature is available on iOS and Android only.

[ming]

In 5118:

Re #1861: Initial implementation of video orientation support

• Utility to resize and rotate video frame
• Support for iOS + sample
• pjsua API to set video device's orientation

[ming]

In 5125:

Re #1861: Changed pjsua API for setting the orientation using a more generic API, pjsua_vid_dev_set_setting() instead

[nanang]

In 5128:

Re #1861: Fixed compile error of 'undeclared identifier PJMEDIA_VID_DEV_MAX_DEVS' when video is disabled.

[ming]

In 5138:

Fixed #1861: Add support for video capture orientation on Android