Avoid failure for newer Scala versions.

Scala stopped bundling an emacs mode, so we have to check whether the
mode is there before loading it.
Setup grep to use Cygwin's find.

Currently uses hard-coded path of Cygwin's find. To be replaced by
clever logic to figure out the Cygwin bin directory.
Configure TeX mode to support texify.
Start emacs maximized.
Configure rgrep.

- search for "agda" files.
- ignore "*.agdai" files.
- ignore "cabal-dev" directories.
Configure prolog mode.
Bind M-. to view tag in other window.