Inside of our networking example code, we have a git2 executable that acts as an entry point to all the different network examples. As such, it is kind of the same like the normal git(1) executable in that it simply arbitrates to the respective subcommands. Let's extend this approach and merge all examples into a single standalone lg2 executable. Instead of building an executable for all the existing examples we have, we now bundle them all inside of the lg2 one and let them be callable via subcommands. In the process, we can get rid of duplicated library initialization, deinitialization and repository discovery code. Instead of having each subcommand handle these on its own, we simply do it inside of the single main function now.
This describes their purpose better, as we now initialize ssl and some other global stuff in there. Calling the init function is not something which has been optional for a while now.
This was not converted when we converted the rest, so do it now.
Relicense examples under CC0
This changes `git_index_read` to have two modes - a hard index reload that always resets the index to match the on-disk data (which was the old behavior) and a soft index reload that uses the timestamp / file size information and only replaces the index data if the file on disk has been modified. This then updates the git_status code to do a soft reload unless the new GIT_STATUS_OPT_NO_REFRESH flag is passed in. This also changes the behavior of the git_diff functions that use the index so that when an index is not explicitly passed in (i.e. when the functions call git_repository_index for you), they will also do a soft reload for you. This intentionally breaks the file signature of git_index_read because there has been some confusion about the behavior previously and it seems like all existing uses of the API should probably be examined to select the desired behavior.
Fixed the filter order to match core Git, too. This test demonstrates an interesting behavior of core Git (which is totally reasonable and which libgit2 matches, although mostly by coincidence). If you use the ident filter and commit a file with a garbage ident in it, like '$Id: this is just garbage$' and then immediately do a 'git checkout-index' with the new file, Git will not consider the file out of date and will not overwrite the file with an updated $Id$. Libgit2 has the same behavior. If you remove the file and then do a checkout-index, it will be replaced with a filtered version that has injected the OID correctly.
I find the showindex example to be pretty useful on occasion, but there were are couple of output tweaks I wanted, plus I wanted the ability to specify a path to an actual index file instead of having to open the whole repository. This makes those changes and expands the example slightly.