This removes the std folder from the tree.
Various parts of the tests are pretty tightly dependent
on std (47 direct imports and 75 indirect imports, not
counting the cli tests that use them as fixtures) so I've
added std as a submodule for now.
This commit adds support for "--watch" flag for "bundle"
and "fmt" subcommands.
In addition to this, it refactors "run --watch" command so that
module resolution will occur every time the file watcher detects
file addition/deletion, which allows the watcher to observe a file
that is newly added to the dependency as well.
This commit moves following tools into a single "tools"
module located at "cli/tools/mod.rs":
- formatter
- linter
- test runner
- coverage collector
- installer
- binary upgrader
- repl
