This commit seeks to improve the performance under batch operations by
holding off compilations until after a period of quiescence. Prior, we
were building every 100 or so milliseconds, but this would cause builds
to happen during batch operations.

Instead, this PR dramatically simplifies the build process to utilize
timeouts to detect a quiet period after which builds can commence.

I also found a missed case while transforming diagnostics into elixir
that caused crashes that took down the project node. I was unaware that
the uri of a diagnostic can be nil (how?!?).

Prior to this PR, mass renames would never finish in emacs, and now they
can.