Add support for Carthage Cartfile and Cartfile.resolved

[pombredanne]

Carthage is a dependency manager for iOS/macOS mostly
See:

• https://github.com/Carthage/Carthage
• https://github.com/Carthage/Carthage#quick-start
• https://github.com/Carthage/Carthage/blob/master/Documentation/Artifacts.md#cartfile
• https://github.com/pombredanne/attributions
• https://github.com/pombredanne/punic/blob/master/punic/cartfile.py

[AyanSinhaMahapatra]

Examples:

• https://github.com/zhuhaow/SpechtLite/blob/master/Cartfile.resolved
• https://github.com/zhuhaow/SpechtLite/blob/master/Cartfile

See also

• https://github.com/search?q=path%3A**%2FCartfile&type=code&ref=advsearch&p=1
• https://github.com/search?q=path%3A**%2FCartfile.resolved&type=code&ref=advsearch

for examples. Here one is the direct dependencies list, and one is the full resolved dependencies list.
Note that dependency relationships are not present.

There are two types of dependencies (example: https://github.com/MacPass/MacPass/blob/master/Cartfile.resolved):

• github:

github "MacPass/KeePassKit" "3.3.2"
github "MacPass/KissXML" "503fc012b73a4507965019720cbf1c157e849657"

• binary:

binary "https://sparkle-project.org/Carthage/Sparkle.json" "2.6.4"

Here we have to check the version: download_url mapping at https://sparkle-project.org/Carthage/Sparkle.json and get the corresponding source archive.