this is more consistent, avoids empty stamp files and should make things simpler
overall.
The slightly tricky `-C` option is added to Catala so that it can be run from
_build while paths to source and destination files are still specified relative
to CWD (Ninja doesn't provide string manipulation, so otherwise we would have to
explicit both the `_build/dir/` and `dir/` versions of each path).
* Obsolete code for included tests has been removed
* The engine uses a proper lexer and is much simplified
* An inline test in the middle of the file now only "sees" the file up to that
point. This fixes an issue where we had spurious errors when a type error was
added at the end of a file, and it would pop up in tests before it. This makes
files including many tests much more practical.
* diffing and resetting the tests has been reintroduced (done at the moment in
Ninja, but for more control (count number of failed tests, etc.) we could put it
back into Clerk at some point
* The Catala CLI can now take an input from stdin (with the possibility to link
a (possibly fake) on-disk file for error reporting and file locations ; this
is useful for running tests)
We need a concrete intermediate target for e.g. transitive uses of `> Include`
for Ninja to correctly handle them.
Of course we could also unroll all transitive dependencies, but meh.
Note also that now tests now just generate the outputs but facilities for
diffing and resetting are temporarily absent.
Rather than require all files to be listed on the command-line (and having to
check consistency with `> Using` directives), the main catala CLI is now a bit
more clever.
⇒ There is a new assumption that a module name definition must match the file
name (up to case and extension) — with appropriate error handling to enforce it.
In exchange, `> Using` directives are now used to more transparently lookup the
appropriate `.catala_*` interfaces and the compiled artifacts for the used modules (handling transitive dependencies), with just standard `-I` flags for when they need to be looked up in different places.
