Use the CocoaPods libx265/libde265 dependency, instead of vendored static library

[dreampiggy]

This is the solution to fix SDWebImage/SDWebImageBPGCoder#4.

Using vendored static library, is a idea for simple C/C++ static library which does not have Xcode project or iOS cross-compiler support. However, it make it impossible to manage the version dependency.

For example, when two Pod use the same vendored library for libx265.a, libde265.a, it cause unavoidable conflict. The solution, it's to introduce a common shared dependency. Since we already make the dependency available on CocoaPods:

• http://cocoapods.org/pods/libx265
• http://cocoapods.org/pods/libde265

So, it's time to remove the vendored library and use the CocoaPods's one instead.

[dreampiggy]

This ${PODS_ROOT}/libx265/source/ is here to fix suck of libheif/heif_encoder_x265.cc, which use x265 like this:

extern "C" {
#include <x265.h>
}

[dreampiggy]

I run pod lib lint --use-libraries --allow-warnings, it passed. However, it seems that Travis-CI have a 10 minutes limit without any std output. 😅 It shows

No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.
Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received
The build has been terminated

Local test:

➜  SDWebImageHEIFCoder git:(project_libx265_dependency) pod lib lint --use-libraries --allow-warnings

 -> SDWebImageHEIFCoder (0.2.4)
...
...
    - NOTE  | [watchOS] [SDWebImageHEIFCoder/libx265] xcodebuild:  503:5: warning: not a Doxygen trailing comment [-Wdocumentation]

SDWebImageHEIFCoder passed validation.

[dreampiggy]

Even with that --verbose | ruby works, the build time is too long for testing. So we just check all subspecs with --no-subspecs option. 😓