biicode support

[Manu343726]

This PR adds support for the libappc library on biicode C/C++ dependency manager.

This contains three simple changes:

• CMakeLists.txt: biicode is file based, dependencies are managed on individual files, but those are usually shared/shipped as a block. manu343726/libappc block in this case. A block, the libappc project in this case, has its own CMakeLists.txt file with build settings. So to support biicode you just have to take care of bii and its block targets in your existing CMakeLists.txt file. Ask me if you have any doubts about what bii does internally and what those targets mean.
• biicode.conf: This is the configuration file of the block. There are settings such as the specific versions on the dependencies the block has (libcurl and google test), and how your existing #includes are mapped to point to the bii blocks.
• REAMDME.md: Badge pointing to the biicode block, and with biicode getting started entry.

The point of adding bii support is that you don't have to manage your third party deps manually through custom cmake scripts. Except libfile (We have no libfile block yet) both gtest and libcurl are managed by biicode automatically from your #include directives.

[mikedanese]

s/manu343726/cdaylward/ ?

[Manu343726]

If do you want to own the libappc block, yep. Create a cdaylward account, change all references to my account, and don't forget to change parent block (See note bellow).